I seem to have overestimated the cost of 4130 tubes as I only looked at two websites which happened to have extortionate prices. Thanks for the websites which I will use as a last resort but has anyone had dealings with any suppliers based in the UK? (which is where I live)

edit: After browsing some websites it seems that the price in the UK is around £7/foot ($11/foot) while I could get all the mild steel needed for a mere £15, so the question still stands regarding the use of mild steel.