Modelmaker looking for advice

Hi, I am an experienced model builder. I have harboured an interest for years in setting myself up to create models for sale, probably through resin casting, for sale on the gift market.

Has anyone here worked with resin, either casting themselves or outsourcing their casting? What are the costs like? I am looking at a casting company, based in Scotland, who seem to be very thorough in their mould making and casting processes. I am sure they charge for their professionalism though.

The only way to make it worthwhile would seem to be in quantity, to be able to cast and shift quite a lot of stock at reasonable prices. Specifically, I am interested in small polyresin buildings, street furniture, architecture, probably with an Irish flavour, as that is what I would be most experienced at modelling.

Can anyone in Ireland create moulds / cast in resin cheaply? What kind of costs would I be looking at?

Has anyone any experience of marketing such models to the trade? Where would you begin, who would you talk to?

Many thanks...