Always best to get a doctors prescription and have it compounded by a local pharmacy but if that is not possible is then there are other options.

This site sells it without prescription -
and even cheaper here -

Can mix 1 x 50mg pill in 50ml of water and take 4.5ml daily.

Buying prescription drugs over the internet is a pretty risky business and not recommended but the stuff these guys sell appears to be genuine. I think gbash buys LDN online so he may know of other sites.