How can i manage to buy some lube?

i am a 14 year old guy, i want to buy some lube to use during masturbation and for when i finally have probs. i know condoms have some lube on them and i bought a pack of condoms off a machine on the wall in the cinema but how do i go about getting some lube? i can't get it online as i don't have a credit card and i would be too embarred to buy some in a shop over the counter. i can't ask my dad to get it for me, we don't have that kinda relationship and i have no siblings. so how do i do it? how can i buy some lube? i am in the UK, Bedford if anyone knows it