Lee
Its not the tapes that they charge by - but the VCD - so they will fill one vcd and charge around 200/300 baht - no matter how many tapes it takes to fill it (or as per your instructions (eg - one tape per VCD)
The Sony Shop in town (in between the two roundabouts) will put tapes onto DVD for about 600 per DVD but as you will be aware you can fit rather more onto a DVD - I do not know if they can cater to the mini camcorder tapes though.
Is it not cheaper and better to get a converter to enable you to play them on a normal size player - and then get one of the kits mentioned above to make your own discs? Suppose it depends on how many tapes you have to do?
I am currently trying to source one of the kits and get it sent out but haven't made much progress yet - as there isn't a real rush for me to do it - but if and when I do manage to get the kit - you will be welcome to borrow it of course

- Depends if you need it done NOW or like me its one of theose things you want to do when you get a moment.
Paul