As they say in England, you pay your money and take your choice. To solder/weld some stainless steel together is one thing, to have a good cheese vat, is an other. I am involved in the supply of dairy equipment and yes, it costs money for a good vat, but it has to be hygenic and conform to many rules and regulations. We have just supplied a 500 l vat, including 2 heating elements, agitator (planet type), lid, measuring stick, semi automatic control for apx. 12,000 euro. I believe that is very reasonable and if you are making cheese as a business, do not cut corners, because you will end up spending money twice.