I've been asked about providing pottery for people to paint a couple of times so thought I'd write about it. I'm not that keen to do this, mainly because I'm not sure bisque fired pots would make it through the post safely.
My method of making pottery is to throw the item on the wheel, then bisque fire it. After the bisque fire it is ready to glaze. At this stage it is very pourous and fragile. Not at all suitable for holding liquids or to be used for anything functional.
I'm not sure what people mean by 'painting' ceramics. I haven't ever used any ceramic paint that may be available from a craft store. I've nothing against decorating pottery purely to look at, I just have no experience in that area.
To create pots that can be used for eating or drinking out of, they would need to be glaze fired after decorating.
As for the pottery, it would be much cheaper to buy ready bisque fired pots to decorate. Most of my time is spent throwing pottery so I can't offer much discount for unglazed pieces.
To decorate, or paint colours on bisque pottery you would generally use an underglaze. I don't actually have any experience in underglazes, I make up my own coloured glazes from raw ingredients.
Once the pot has been decorated to your liking, it would need to be dipped in a transparent glaze to be functional.
This process is what you would find in any paint a pot studio. There are lots of these about, if you are just getting started if may be worth approaching them to do some sort of deal. You could collect some bisque ware, take home to paint with underglaze, and return the glazed pots for the studio to fire for you. I'm sure most of them would be happy for the extra business if they charged a fee per pot fired or something.
It's important to match the bisque ware, underglaze, glaze and kiln firing temperatures. Most liking for functional stuff you should be looking at the stoneware temperature range.
If you want to do glaze firings yourself you would need a kiln. This can be very expensive, though I did buy mine off Ebay for a few hundred pounds. You really need to locate a kiln in an outbuilding or shed. The glaze firing will reach temperatures of around 1200 Celcius, and there could be fumes which you don't want to breathe in. Some small kiln will run off a standard plug socket. The medium to large ones would require an electrian to provide a special supply and hook the kiln up.
I link to my supplier in this article. I use them mainly because they are the closest to me, you could find others near you searchng 'ceramics suppliers' or 'potter supplies'.