I need memory that'll run at 245MHz & is double-sided

[lookin4dlz]

I want to spend the least $ I can, preferrably less that $250 for 1GB (2x512)... It looks like PC3500 has tighter timings & is less expensive, but can it overclock enough?
What about some less known brand like this: Atlas Precision Brand - Highest Grade - 512MB PC4000 $114.50 ?

Thanks!