My family is by no means wealthy, but my future in laws struggle more financially. My parents seem to want them to contribute despite this fact. Do any other brides have troubles with their parents (if you are being traditional where the brides family pays for most of the wedding) wishing that the future in-laws would contribute more money towards the wedding? How do you deal with this? It puts me in an odd place...
First and foremost, make clear to your parents that they have no right to expect any financial contributions from the FILs, that the FILS will not be asked to contribute financially, and that the subject is closed.
Then, plan an affordable wedding with the funds you have available.
PP have it covered, but I will tell you my personal experience. My parents paid for our reception and my dress. They offered to pay for more, but we declined and paid for everything else ourselves. But when we would see my MIL, my dad would joke to her that she had to pay for the "traditional" things the grooms family would pay for, the RD, booze at the wedding, and flowers. My MIL was in no condition to pay for anything, especially since my H was paying her property taxes for her.
So I took my dad aside and told him he needed to knock it off. I knew he was joking, but my MIL was worried that she needed to pay for things. My H & I kept telling her not to worry about it and I also told her my dad was joking. My dad didn't realize that she wasn't getting the joke, so he stopped making them.
Now, I know there is a big difference between joking about paying and your parents wanting your FILs to pay. But you still must act the same. Tell your parents that you will not and cannot ask your FILs for money for the wedding. You don't have to tell them why they cannot, just say that they cannot. I never told my dad that my H was paying my MILs taxes, I just told him that she couldn't contribute and to stop with the jokes.