It's going to be wonderful, don't worry!
Few ideas from mine:
My mom and sister made all my flowers from paper and cloth as I did not have the budget for centerpieces (quotes were seriously in the thousands hahahaha). Instead of vases I saved all our espresso cans for a year (they are pretty bright cans, that's my style) and we stuck frogs in the bottom of the cans and anchored the stems in. Super cheap. They were beautiful and I still have them all.
My mother and I went to a discount fabric place and found several different partial rolls of lovely semi-opaque lacy cloth in complementary tones. Super cheap. She cut them out, didn't even hem as who would notice, they looked amazing.
I got about a thousand tea lights and put them all over the place. Again, super cheap.
We had an area of flat wall so brought a laptop in and projected a movie onto it -- just a cool old vintage movie played silently for background color. I forget what it was, DH chose it.
I did not do this but other brides who used the same space hung white Xmas lights around not just against wall, but looped down from ceiling across the room this creates a canopy of fairy lights.
And my dress cost $85 (which is what, around 140 pounds?) in a vintage store and everyone loved it. You'll make it work. If you're into vintage and DIY charm this is a great blog for ideas. ruffledblog.com/