Memory tweaking on VPS?

[NiceAndEasy]

I've been on a VPS leve 3 plan with hostgator and for about a week now Ive been getting 500 errors and small timeouts (apparently, mostly on my wordpress end). Hostgator told me that Ive been hitting the memory limit of 768MB and told me they only way to increase this is by switching to level 4. Unfortunately that is 30 bucks more that I dont think I can afford just yet. Besides, Ive gotten many suggestions from others how to work around the issues such as implementing mod_php, eAccelerator or set the read/join buffers in the my.cnf. Does anyone have experience with these things? How can I analyze what the best my.cnf setting are for my site? Im pretty much a noob when it comes to server tweakings and dont want to mess up anything - but I do know things can be improved without going to a new level. Thanks for any advice!

[~ServerPoint~]

What is the price of VPS you can afford I wonder?

[AdrianG001]

I would suggest to increase memory - more memory, faster website :-) But if speed is not important, reduce all cache sizes, set php memory_limit to 8M, disable opcode caching (APC, eAccelerator) or try Raspberry Pi as server, now comes with 512MB :-)