Polo centre caps might fit, but genuine ones are not cheap.
eBay specials are cheaper but be wary about quality. I bought some for my Octavia wheels. Even though at 56mm they should have been a good fit, the cheap brittle plastic meant the lugs didn't bend properly and the first two broke trying to get them in the centre hole. Threw the remaining two away.
TBH, i'd go with the stickers if they're reasonable quality and look ok. Just give the caps a good clean before you put the stickers on.