Sequence is fun and it's under $20. We like Yahtzee, too. Pictionary is fun but I don't know how budget friendly it is.
How about some card games? They are budget friendly. Skip-Bo (if you don't already have it) is good. Mille Bornes is a card game I ordered from a catalog last year. My dh used to play it with his family and now we all enjoy it. This year, Target is selling it for under $6.00.