It depends how far you want to go with it, I wanted mine to be a salon at home not just a converted shed, i have all the equipment a salon would have and stock as I want my clients to use professional products, that's where the money goes. My house insurance went up and you need to be covered for slips and trips which was £150 I think? Plus your own liability insurance, if you play music/radio that's £171 a year, if you want staff you deffo need planning permission. If your local council want you to have planning permission that can be quite pricey and time consuming but once it's done it's done. I also have a toilet and kitchen in mine to stop ppl from going in my house (I am not tidy enough!! Lol) so plumbing is a cost... everything in salon needs to be pat tested once a year or insurance is invalid, I think that's it. Salon equipment is quite pricey too, realistically your probably looking at 10k to get everything you need and decor etc xx
