Umm I get it from my GP. The first time I got prescribed it I was only given 7x5mg tabs because it was the first time I'd had them and due to their addictiveness I wasn't permitted to take them for more than a week. I then saw a different doctor (back home - not at uni and so they didn't have my recent records) and played it cool saying I'd taken them for 4 months and I take 5mg prn which equalled out to about 1 per week just to help me. He seemed fine with this and prescribed me 28x5mg.
I took them within about 10 days and got addicted, tried to withdraw and went cold turkey and had really bad withdrawal symptoms (loads of sleeping, shaking, twitching, sweating, severe headaches) so I went back to the doctors and they had to prescribe me some more so that I could take them and then slowly ween myself off of them. It didn't take me long to ween myself off of them so I had a lot left over.
And lately I've had terrible sciatica and was prescribed some more valium (28 tabs) to help relax the muscles in my back and numb the pain. I was also prescribed painkillers, 30mg codeine, 20mg dihydrocodiene, 50mg tramadol and also 750mg methocarbamol so I've not actually used any valium at all. From being prescribed them in the past and keeping them I've got about 10x 5mg tabs and 35x 2mg tabs tucked away - so a fair amount.
That said, for anxiety, doctors aren't going to dish them out willy nilly (or other benzo's for that matter). If you REALLY want them, they're usually one of the first medications prescribed for sciatica so depending on how good your acting skills are...
There's a similar drug on the market called Etizolam which is chemically similar to diazepam. It's widely available online (about £1 per pill) and I've heard fair results about them - although I'd prefer paying £7.40 for a prescription of 28 pills as opposed to £28 + postage for unprescribed medication off of the net...