[quote name='yayece']My 2 cents on "memory cards." There's actually 2 things that people could be talking about. Both are optional.
First, is a "memory card" which holds your save game data. It's not really necessary since the Saturn has some onboard memory for your save data. I don't recall the exact numbers, but Saturn saves maybe took up a few "blocks." Onboard memory had a few hundred blocks, and the memory card had maybe a few thousand blocks. I don't remember it being a big deal not having one of these. That's probably why the prices on these is a bit inflated. 1 caveat about the onboard memory... It's RAM+battery based, kind of like the NES games of old. You need to have a watch battery (CR2032?) in there to actually save your games. If the battery dies, your saves are gone. You can replace the battery while the system is on and not lose your saves.
The 2nd "memory card" is a 4MB RAM expansion pack. Capcom used this a lot for its import-only games (Xmen/Marvel vs Street Fighter, DnD Collection, Darkstalkers, Pocket Fighter, etc). It used this RAM pack to load all the sprites into memory, allowing for arcade perfect ports. A lot of these games are superior on the Saturn compared to the PS1's versions.[/QUOTE]
Eh, the "backup RAM" cartridge is probably expensive because it's practically necessary. There's no way I'm able to contain all the saves of all the games I've got on my Saturn's onboard memory.
The 4MB RAM is good for particular import games, of course. There was also a 1MB RAM cartridge that was mostly used for Neo Geo ports.
One thing to consider is that you should really go with the official carts only. Unofficial carts tend to have thicker circuit boards that bend the extremely fragile pins of the Saturn's cartridge port too wide. It's also been said that the cartridge port is simply unreliable in general if you do too much cart swapping. The good news is that my cartridge hasn't been removed from my Saturn in years, so my console's still rock solid.
Personally, I'd totally skip the 4MB and 1MB RAM carts and the imports associated with them. Better ports of most of the games exist nowadays, and the ones that don't usually work fine when you're emulating their originals. Really, what would you rather play? Saturn Street Fighter Alpha 3 or the PS2 SFA collection? And even though I've got two backup RAM carts, I've never even really needed the second one. I got it just in case. The carts have an extremely large amount of space available.
EDIT: One more thing about memory cards and carts from the 32/64-bit era. Third party cards generally sucked. Hard. Their failure rates were through the roof. Spend the extra money and go for the real thing. In addition, I read some technical details about 3rd party Saturn carts back in the day that explained why they failed so much, and many of them operated at a different speed due to compression. That threw the timing off in certain games, and saves got corrupted.
I've had zero problems with my Dreamcast Innovation 4x card, though. If you can find an Innovation or Nexus 4x or 16x card, especially with a PC link cable to backup your saves even further, I'd jump on it. Unfortunately, I don't know if the software support is there for it anymore. That, and it uses a serial port which is outdated these days.