Well, it really depends on what you're trying to do with the tweets, i.e. simply retweet them immediately...gather them and store in a database...respond when certain words are triggered, etc...
I had a pretty simple retweet setup that I used with Yahoo Pipes previously. You might be able to go over there and mess around a bit and come up with something that meets your needs in the short term until you can afford a paid solution like TweetAttacks.
Anyway, check it out as I was doing some pretty elaborate stuff with the pipes yahoo makes available...you can even find existing pipes, and figure out how they were designed, and how they work. Then you can use those as models to create your own pipes that exactly match your needs.
Good luck, and I hope it helps.