Stronghold off the Internet

[Greedycat]

Do any of you buy stronghold off of the Internet? I have noticed that it is cheaper to get it online than from the vet but how can you be sure that it is the genuine stuff ? Also do vets charge for prescriptions because you can only buy Stronghold if you have one?
Also I am wondering if any of the cheaper flea treatments work because I am finding Stronghold at £32 for three months supply quite expensive!

We get Stronghold from VetUk.co.uk and I'm pretty sure it's the genuine stuff. It works, anyway! Our vet does charge for the prescription, £9 I think, but it's still worth doing it that way as a 6 pack is only £24.05 instead of £45 ish at the vet...
Cheaper stuff didn't work for us, even though the price of Stronghold makes me cringe I have do really appreciate not having fleas. You don't really appreciate how lovely it is not to have fleas until you've had them!

We buy advocate off the internet, a private prescription costs me £8 and I go through Quidco or topcashback to get an extra few % off the price.

The vet's seem quite used to writing the prescriptions.