Find me some flights!

Hello all,
Not sure if this is the right forum for sure, but I have somewhat of a challenge for anyone who's interested - and I'm playing it too.
I just discovered I'll be getting a healthy tax return and want to put $250 toward doing some flying.
Here's the constraints, must leave on a Friday from SEA after 6:30pm or as early on a Saturday as possible and it must return to SEA by 8pm on Sunday.
Ideally I want to fly on as many flights as possible to as many airports as possible for $250 or less RT.
So far the best deal I've found involves little flying, but a good chance to spot: SEA-SFO for $126 or SEA-LAX for $140.
Wondering if anyone can find me anything I can't!