Decent grip replacement is about £7 each if you get a pro shop to do it for you. You can do it yourself but there's likely to be a learning curve, so maybe be prepared to get it wrong and waste a grip or two.
Have a look at the Costco set. They were doing a full set of Callaways, with putter and bag, for about £550. The Kirkland balls are supposed to be pretty good too.
Lamkin grips are good value. If you know someone with an air compressor then can easily do it yourself.
I haven't changed a grip myself but I'm sure you don't need a compressor, just a good eye and some decent glue. All I'm saying is if you are buying second hand clubs it's a bonus if the grips are in decent nick because it could be £75-£100 to change a set .
I’ve changed around 120 grips over the years. I cut the old ones off with a Stanley knife and blow the new ones on. Takes about 5 minutes. No glue no petrol, and they don’t twist.