can you recommend me a website where I can buy whiskey glasses?

Amazon

EBay

Esty

Wal-Mart

Jan nailed the sites pretty good but it kind of depends on what you want to spend on them. Decorative or for use ? Another site for you to look at but Amazon is probably your best bet.

Buy Whiskey Glass from Bed Bath & Beyond

Dear John Petkov,

Others have given you good websites, however if you enjoy shopping you can have lots of fun going to second-hand stores.

They often have unusual and beautiful glassware you cannot even buy anymore, and reasonable too (avoid antique stores, however).

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And btw, welcome to Blurtit, hope you enjoy and stay a long time.