6502.org

Are you outside the U.S.? Within the U.S. especially, it's easy to get new 65c02's. They are in production. Outside the U.S., people say the shipping costs are a killer; but you can check out the availability in our sticky topic on where to buy them, at viewtopic.php?f=1&t=1953 which we try to keep up to date.

4KB address space should be more than enough to get started. And building a retro computer with real retro parts feels better than ordering a brand new 65C02.

A system build around the 6503 would be real fun to see. The 6503 is close to the 6504, also a limited 6502 in address space.

As the more experienced users will point you to the latest and greatest 65c02 or 65c816 with lots of memory, quite something can be accomplished with an NMOS like the 6503, with a lot of building fun, in 4K space.

The KIM-1 had less to start with. And it could play chess quite well and run Tiny basic.
Porting Microchess or Tiny Basic to a 6503 system would be a nice exercise.

Just have a look at the small 6502-6532 systems on my website like the Beta or the Cepac or EMUF for inspiration what you can do with such a small system.

With a 2K (EEP)ROM, 2K RAM and a small I/O space with some simple decode logic it can be a nice and entertaining learning experience. Or use a 6532 and you will not need extra RAM at all!

Just go ahead!

Very few people, I think, actually write large complex programs on 6502, so the main practical disadvantage would be the inability to squeeze a full Basic on there, or one of the larger assembler/monitors.

(Garth and BDD are among the exceptions: they do use 6502 to a full extent. As noted, TinyBasic could probably squeeze in.)

Could try RAM bank swapping/paging.