unfortunately at least as far as i can find, any apple II's, Commodore 64/128 etc or other similar era hardware are just to expensive to buy, everything i find on eBay is $150 upwards and being a university student its the old issue of lack of funds. unless anyone knows something i dont about where to get old systems in Australia or wants to donate one then i think i'll have to buy some new chips from mouser
Interesting, ebay.com.au has nearly no C64 auctions (if you search for C64). In ebay.de there are lots of them. But you could order the individual chips. I don't know the seller, but this auction is still online:
http://cgi.ebay.com/170828631732US $2.54 for a 6502, and free shipping doesn't look to expensive. But it is in China, if I order it from Germany usually needs 4 weeks or more delivery time. But I have good experience with it, once I ordered a lot of MC6850 UART chips for my
Kerberos cartridge from China and they all worked with no problems. Very useful chip, if you want to implement a serial port on your system. You can get them, too, for cheap on Australia eBay, again from China. It's crazy, cost with free shipping is less than the shipping cost alone would be if I would send you one:
http://cgi.ebay.com.au/191964446415But I couldn't find a cheap 6522 VIA.
For the RAM and ROM, I would just use modern parts. See e.g. my Kerberos cartridges (schematic in my github project page for it). It provides 128 kB RAM extension and 2 MB flash memory, besides the MIDI ports. I used a CY62128EV30 SRAM chip. You can tie A15 and A16 to GND and then you'll have 32 kB RAM for your system for less than 2 bucks (you can get it from Mouser and Digikey). You'll might need some logic gates, too, for decoding the addresses and chip select. Note that you need some voltage level translators as well, like the 74LVC8T245, because the RAM operates with 3.3V. I guess there are cheap 5V SRAM chips out there as well.
For the second 32 kB you can use a flash, like on my catridge. But this is available with 5V supply voltage as well, e.g. SST39SF010A. So for a start, you could just use a 6502 and a flash, then program a blinking light by toggling A15, or something more fancy like an 8 bit digital output with a 74373 and related trigger logic. If you use the outputs of this chip, you could even implement bank switching. It's all too easy these days, no need to use complicated DRAM chips.
For flashing the flash, I used my C64 in combination with the CPLD (and for fun built
a programmer with a Raspberry Pi), but it works with a TL866CS, too, a universal programmer that
Dave tested once:. Relatively cheap on ebay:
http://cgi.ebay.com.au/191736125106 Very useful device, can read old EPROMs and ROMs, too.
If you don't have already many gates for testing on a breadboard, maybe design a circuit first (which is the most fun part anyway, at least for me), then you'll know what you need to buy.