Intel are releasing 3 new pentium - budget processors based on the sandybridge platform - on may 22nd. I'd suggest them but if you can't wait you could always go for the sandybridge i3 2100 or other SB i3s if you want something with a little more power.
If you want cheaper get one of the newest available pentiums. The Pentium Dual-Core E6800 is pretty powerful for a pentium and is $100ish, but you can get cheaper ones, the i3 2100 is $125 of amazon and the new pentiums will be between $50 and $100.
If you want you could go for AMD athlon IIs, they're good value but not as good performance as intels overall.