750 is not so bad.
Break it down.
Lets say you can get £200 from family and friends.
Do you work in a place with more than 50 people? If you do how about a bonus ball sweep stake? Choose a number (pull from hat) £10 each for 10 weeks (£1 per number per week). Winner each week gets £20.
Income = £490, outgoings =£200, profit = £290.
So you now have £200+290 = 490.
Do other things as a team, charity car wash? Organise a Ball? (£20k raised one year doing this), race night or quiz in the local pub? (just putting a tin plus a little poster saying what you’re doing on the bar will get you £50).
As a team why not approach sponsors? We got £1000 from Duncan Ballantyne one year when raising money for the NSPCC.
Flog space on your jerseys to local business, or even big names, you’ve just got to ask, if they say no, move on, it’s a numbers game.
Football clubs will often provide signed kit for you to auction if you pitch it correctly.
Charities themselves ofter have loads of suggestions and can offer support and promotional material (or make some up yourselves), even if it’s arranging for you to stand by the till at B&Q with a tin (I made £120 doing this, so that’s £610 without even trying).
Good luck, I’ve done quite a lot of fundraising over the last couple of years for the NSPCC and for the local school so I know it’s daunting but it can be a lot of fun and is very satisfying.