Back in the mid 1980s I was without a bike. My mate sold me his grannies bike for about £2.50 or something like that. It was a proper sit up and beg bike with the metal rods for the front brake.This is what i have done today, I went to the bike hub just off Lewes Rd, Got an old hard tail trek for £110, I'll use locks but tbh it looks like it's worth nothing so won't get stolen for resale, They sell abandoned bikes etc, these have a sort of service and a quick check over before being sold with any damaged or faulty parts replaced or fixed.
I rode it along the Old Shoreham Road and left it parked round the back of the Hove Tavern. I had no lock, but didn't think anyone would pinch it. They didn't.
It poured down all game and rained all the way home as well.
Had the bike for some months after that, used to go shopping with it - and no-one ever pinched it!
Bit like this sort of thing
That's what you need - you'll be fine.