My best tips:
Netbride for dresses - find a style and they will give you a free email quote. I asked for a quote 5x (over a few months) on my dress and got a price of $300 - it was $800+ in the salon.
I had one bridesmaid and found her dress -new with tags - on eBay for $21.21 with shipping. I just searched for her size and the color I wanted (it was 1 size too big and she paid alterations) I took a chace that she wouldn't like it, but at that price, she was glad to have a nice dress that she could wear again. She told me later that was better than having to spend more on a dress she had to go out and find.
Easy centerpieces can be flower petals, tealights, or any combination.
My centerpieces were "silver" trays I found at the Dollar Store, 3 tea lights and white rose petals. Search for freeze-dried flower petals online - I used them and I think I spent around $25 for enough to sprinkle over 15 tables. They're great - soft and real but they don't turn yellow and they last for weeks! The centerpiece total for each table was about $2.50 each.
Favors - forget them! If you want a cheap alternative, buy cardstock and print a poem to create bookmarks. Some ribbon at the end finishes them off - I bet you could do it all for $10 or less!
At one friend's wedding she had 1 candle (small) as a centerpiece and sprinkled candy Kisses all over to work as both centerpieces/favors for guests to eat.
Flowers - I just bought the "essentials" I wanted. Bridesmaids can carry a single flower, for example.
Shoes - mine came from Payless - $7!
A friend might like to "donate" her services to create a guestbook. I made one for my wedding shower that was a labor of love and its still a favorite memento. It was a small scrapbook -craft store- and each page was left for people to sign.
Craft stores have great print-yourself invitations now - usually $20+ a box.
Personally, I think the most beautiful weddings are the simpliest - focused on friends and family so I'm sure it will be wonderful. Good luck!
