brennaandtoby's Yellow wedding

I'm 99.9% positive we are going to be having the reception in a big white tent. It's going to be in the field behind Toby's parent's house, a little away from the ceremony (in the apple orchard not even 1/4 of a mile away). I can't see how we can get away with not having a tent, especially for weather reasons. I was really bumming about this for a long time because they are RIDICULOUSLY expensive, but with my parents saying they'll boost up my budget (double!) and pay for it all, I feel a little better about paying for it.

Anyways, we will most likely decorate the inside ceiling ourselves. Do any of you girls have any ideas on how to decorate it nicely, and in a fairly inexpensive way? I was thinking maybe tulle or something. Maybe alternating the colors light yellow and light green? Would light green be too dark to put on the ceiling? It is a semi-formal/"business casual" wedding, so I don't want it to look too formal, but I also don't want to see the metal bars of the structure! Any ideas?

I'm not completely shut off to the rental company (TBA) decorating it, but I hope to find something less expensive and more creative.