Why one quote says ฿3,000 and another says ฿30,000

Check these three things and you will know whether you are comparing the same thing at all.

One — how many pages, and what is in them

A page with a form and a page with a booking system both count as one page, and cost very differently.

Two — can you edit it yourself

The admin is invisible from the outside and takes real time to build. A site you cannot edit is always cheaper.

Three — who looks after it afterwards

A price that includes cover and revisions is not the same price as one that ends when the files are handed over.