I paid for my own wedding so I would say that any amount of money that you or the brides parents kick in would, and should, be a blessing. Pay what you can afford and if they don't like it, they can scale back the wedding.
Word for word what he said.
And another vote.
And ANOTHER . . .
Back in the Stone Age when we got married, we decided to pay for our own wedding. That was fine by the in-laws-to-be and they said "good luck" and have a good life. My Mom wanted to help out and pay/provide for something, so we "let" her and Dad host a picnic after the rehearsal. Oue wedding, flowers, wedding dress, tux for me, pictures, reception, invitations and anything else cost us about $600 (1976 dollars). We are still married and looking forward to many more years.