Tell your parents about the type of the trampoline and why the size and shape works well for your yard. Don't pick one that is too big.
Go to a Trampoline review site- learn everything on how to
stay safe, then find one you like and which fits into your budget. They
will be proud that you did research on all dangers of trampolining (and
benefits, of course).
If they still aren`t into it, maybe it`s a good idea to take them to
trampoline park, they can try it out and stay amazed how much fun it
Beg, pout, jump up and down on the couch... that should work
Trampolines are fun, and kids know this even before they’re tried jumping on one. Parents appreciate trampolines because they offer a chance for their children to vent all their pent up energy. But sometimes kids need to convince their parents to buy a good Trampoline.
You have to realise your parents about the importance of trampoline. Nowadays trampolines are a great way of fun for kids.Trampolines are used for kids for mind fresh, body fitness, baby sports.
Get money get a job. THEN worry about buying a trampoline
I really love Trampolines
Well, you can try to find some kind of profitable trampoline purchase option. In fact, if you search, then I'm sure you can find it. I think that you can try to search here https://trampolines.guide/. There are a lot of good trampoline options here. Show these options to your followers and try to persuade. Might work
Save your pocket money or move lawn to earn money for it and have the satisfaction of owning it. Parents also have to work for it.