I bought a Vasart Tulip Lamp for just under £100.00 (antique shop) in October 2004 and sold for £155.00 on eBay.
Seeing that they now generally sell on eBay for around £200.00 is proof as Frank says they have and are growing scarcer.
However you can still buy for around £100.00 in many shops in Glasgow shops like 'Relics' or 'The Victorian Village'
Edinburgh is expensive but Glasgow is still good to buy retail.
There is a lot of Monart and Vasart still on the street in Glasgow. I live in the West End and most windows I pass have pieces of Monart, Vasart and Strathearn in the window. One house has a shelf right up against the window, with about 30 pieces of glass I assume to be Vasart - I really want to take a picture but am scared I will get my 'collar felt' for casing the joint LOL
The auctions are good as well -
McTears & Co www.mctears.co.uk
Anyone with a larger pocket should head for http://www.timwright-antiques.com/
see Monart section - he has a lot more in store - I think he is the most expensive dealer selling Monart/Vasart in Glasgow - he does get large pieces with original labels and he gives good discounts