Pilla FLASH, que son también baratas. Empiezan por 28F, y a mi mis dos 28F020 me costaron unos 2€ desde HongKong
Sobre mappers, aqui tienes unos cuantos que valen la pena:
The MMC5 was Nintendo's largest mapper. It was also the most expensive, making developers avoid it. Only Koei seemed to use this chip regularly in their games once it was released. The chip has 1 KB of extra RAM, extra sound channels (two square waves), supports vertical split screen scrolling, improved graphics capabilities (making 16,384 different tiles available per screen rather than only 256, and allowing each individual 8x8-pixel background tile to have its own color assignment instead of being restricted to one color set per 2x2 tile group), highly configurable program ROM and character ROM bank switching, and a scanline-based IRQ counter.[7]
Manufacturer: Konami
Games used in: Akumajou Densetsu, Madara, Esper Dream II
The VRC6 (Virtual Rom Controller) was an advanced MMC chip from Konami, supporting bank switching for both program code and graphics as well as a scanline-based IRQ counter. The chip also contained support for 3 extra sound channels (two square waves and one sawtooth wave). It was used in Akumajou Densetsu (the Japanese version of Castlevania III: Dracula's Curse), while the western version used the MMC5 from Nintendo. Since the NES, unlike the Famicom, did not allow cartridges to add additional sound channels, the soundtrack on the western versions could only access the original five sound channels built into the NES.
The VRC7 with a post-processor for the FM synthesis.
Manufacturer: Konami
Games used in: Lagrange Point
The VRC7 was a very advanced MMC chip from Konami, not only supporting bank switching and IRQ counting equivalent to the VRC6 but also containing a YM2413 derivative providing 6 channels of FM Synthesis audio. This advanced audio was used only in the Famicom game Lagrange Point; while the Japanese version of Tiny Toon Adventures 2 also used the VRC7, it did not make use of the extended audio.
NAMCO106
Manufacturer: Namco
Games used in: Erika to Satoru no Yumebouken, Final Lap, King of Kings, Mappy Kids, Megami Tensei II, Nacmo Classic II, Sangokushi 2, Youkai Douchuuki
NAMCO106 was an advanced chip using 4-bit sample table synthesis, that supports up to 8 extra sound channels, with aliasing increasing with the number of active channels.
PD: Si pillas alguno que no te guste, me lo revendes