Wedding Anniversary on a Tight Budget?

I hosted both my parents and my in-laws 30th wedding anniversary parties. We were very low on funds. Here is what we did for them:

In-Laws:
Had a set number of invitations (it was 50 I believe) We made the invitations on the computer, used a single piece of paper and then "tri-fold" and used the back of the paper as an envelope.

Had a sheetcake made by two of the sisters and I made one to feed the guests, I made a "fake cake" out of styrofoam circles and Laundry detergent flakes, using the original topper and that was the centerpiece.

I made a bouteneer (sp?) for FIL and a Coursage for MIL. Other than that, the decorations were their wedding pictures and her dress/veil, as well as the fake cake.

The only thing we splurged on was napkins that had their names on them, and the years. With the hall we rented, invites, stamps, decorations, and napkins, it all only came to about $125.

With my folks:
Invitations were the pkg ones from WalMart, that were elegant but plain. I just made a couple sheet cakes that said Congrats and had the years on them, their original topper and wedding photo was the centerpiece for that table. We served coffee and tea for drinks. For the rest of the tables, I got a fluted "fish bowl" from the craft section at WalMart. I put on in the middle of every table, with "confetti" underneath. The bowl was decorated w/ribbons/pearls and a floating rose candle in the middle. We went ahead and again, splurged on the napkins that had their names and years. This one cost about $75 for us.

I forgot to mention that these were come and go affairs, like from 2 pm - 4 pm. I would think that you could still implement many of these things in a more formal setting with a dance. I hope that some of these suggestions help and that you have a wonderful anniversary!