Battletoads & Double Dragon NES $15-$60

In this beat-em-up...Rash, Pimple, and Zitz from Battletoads, and Billy and Jimmy Lee of Double Dragon fame, team up to take on the forces of evil. The game was also available on the SNES and Sega Genesis...but the NES version is the hardest to find of the three. I would not really consider this game to be "rare" (especially when comparing it to some of the later games I have on this list), but it is definitely a lot less common than most other NES games. It's very hard to come across this in a pawn shop or used video game store (or as collectors like to say "in the wild")...but you will probably never have trouble finding a copy of it on Ebay. It usually sells for around $15-$20 if it's just the game cart only (or "loose")...but if it also comes with the box and booklet (CIB, or "Complete in Box"), than it will probably sell for around $40-$60.

Tetris (Tengen Version) NES $15-$60

This is probably the most well known "rarity" on the system. Back before Nintendo released their Tetris...Tengen (who had been making unlicensed games on the NES) released their own version. Nintendo filed a lawsuit against Tengen, and they were forced to remove their Tetris from the store shelves...which was quickly replaced by Nintendo's version. This game used to be considered one of the most rare games on the system...but people have discovered over the years that it is a lot more common than they originally thought. Sure, you most likely will never find it in the wild...but there have been tons of copies popping up on Ebay. A loose cart will sell for around $15-$30, while a complete copy typically goes for $40-$60.

Contra Force NES $30-$80

Don't let the Contra name fool you...this game is complete garbage. In fact, it originally wasn't even meant to be a Contra game...but Konami figured it would sell better if they slapped the Contra name on it. The game is filled with slow and clunky game play that can't even begin to hold a candle to the greatness that is Contra and Super C. Still, because of the rarity of this game when compared to the other NES Contras, it sells for a good chunk of money. It was also never released in Japan, and was a U.S. exclusive. Despite having about the same rarity as Tengen Tetris...it sells for a good deal more (most likely because it bares the "Contra" name). A loose copy on Ebay will set you back about $30-$40, while a complete copy with the box and booklet usually goes for around $60-$80.

Ducktales 2 & Rescue Rangers 2 NES $30-$120

The original Ducktales and Rescue Rangers NES games are some of the most well loved platformers to appear on the system other than the Super Mario Bros. trilogy. While the originals are very common, and usually never sell for more than $5 each (unless they are complete)...their sequels are a whole different story. Both Ducktales 2 and Rescue Rangers 2 were released in 1993...late in the NES's life. They also both had somewhat limited production runs (as did many NES games that were released in those late 8-bit days, when the 16-bit systems had already taken over). Thus, both Ducktales 2 and especially Rescue Rangers 2 can be pretty hard to come by...making them worth a lot more than their predecessors. Both games were basically just re-hashes of the first Ducktales and Rescue Rangers, with new stages and a couple of other new things tossed in. So, most NES gamers who don't want to pay a hefty price will probably just want to stick with the originals. Ducktales 2 (being the more common one) will usually sell for around $30-$40 when it is the cart only, and around $80-$100 when it is complete. Rescue Rangers 2, which has recently started going up in price, will run about $40-$60 for a loose cart, and $100-$120 for a complete copy!

Snow Brothers NES $60-$130

Originally an arcade game made by Toaplan...the NES port was made by Capcom. It is similar in gameplay to Bubble Bobble...only rather then trapping your enemies in bubbles to defeat them, you must trap them in snow by throwing snowballs at them. Once all the enemies in a level are defeated, you move on to the next. A fun and addicting game, it's at its best when you are playing two player co-op. I have noticed a larger amount of copies of Snow Brothers showing up on Ebay recently...but the demand for this game remains very high, and it still fetches pretty hefty prices. Expect to pay $60-$80 for a loose cart, and $100-$130 for a complete copy.

Little Samson NES $100-$300

Now we're starting to get into some of the real biggies. These are the games that you might have to take out a mortgage on if you want them in your collection. While Little Samson may have the same rarity rating as Snow Brothers and Fire 'N Ice...it commands a much higher price due to having the reputation of being one of the better games on the NES. The game was released in 1992, but sold poorly...thus it was retired off the shelves pretty fast. However, if people had given the game a chance...they would have seen that it is a very solid title. Little Samson's gameplay is very similar to Mega Man...with your character being able to shoot projectiles at enemies. The game has four playable characters - Little Samson who is a human, Kikira the dragon, Gamm the golem, and K.O. the mouse. Each character is level specific...but you can go back to levels you have already completed and switch to any character you want. This game could have gone down as one of the great NES classics had it sold well...but unfortunately, it was released during a time when 8-bit games were considered to be over the hill. So now, it costs a small ransom on Ebay due to not many copies of it being released. Brace yourself for this one's price range...a loose cart goes for $100-$120, while a complete one goes for $200-$300! Expensive, right? Well, you ain't seen nothing yet!

Bubble Bobble Part 2 NES $100-$300

Bubble Bobble Part 2 seems to have about the same rarity and demand as Little Samson. Thus, it fetches about the same price on Ebay. The game was released in 1993, and as you would guess...it didn't sell very well due to being released on a dying 8-bit system. Wikipedia claims it was a rental only, but other sources say it was available for sale in stores...so I'm not really sure on that one. As you would have guessed, the game brings back the gameplay from the original classic...only the levels are new, and the graphics have gotten an obvious face lift. There is a game out there called Rainbow Islands that frequently gets mistaken for Bubble Bobble 2, despite them both being completely different games. Even on Ebay, you will see people constantly listing it as "Rainbow Islands: Bubble Bobble Part 2". While Rainbow Islands usually sells for around $10-$20...the real Bubble Bobble 2 will cost you around $100-$120 for a loose copy, and $200-$300 for a complete copy. As I mentioned...basically the same price range as Little Samson.