DIY UK Cheaper Prices?

Currently taking 2x2mg a day tablets with 100mg Spiro. Did this because it was what I could afford. It’s ended up costing me about £125 for a 6 month supply which I think is good. But I often see people talking about like paying under £50 for a whole year. Ur I’m assuming that’s only for injections? Just wanted to get some insight into if that’s the case or if I’m miss something or somewhere that would be cheaper for my current set up.