Probably best to go to Sports Direct or use M and M direct, they normally have good offers. I have found you get what you pay for though i got some cheap bottoms from tesco and asda and to be honest there rubbish haha. So a couple of week ago i went to sports direct and got a under armour t-shirt for £11 and a sleeveless nike t-shirt £9 and some adidas bottoms for £25 i also brought some compression bottoms and tops they are by a make called sondico and i think they are more of a football brand and they are about £8-10 each. I also got a nike livestrong t-shirt for £10 from tk maxx. These are all dry wicking which does make a massive difference for training in. I didnt believe it at first but it really does make a difference. I will probably some nike compression stuff next as it is better quality.
What im going to do is buy a couple of bits each month with the money i save from not drinking haha.
By the way im no expert on any of this lol and its just my opinion, hopefully someone with a bit more knowledge can help out more.