Oh yeah sorry mate I forgot about the low limits at the start. It also increases after 3days, then 7days etc too as well as every time you buy (think you have to wait 24hours tho). My first time I had to buy in 3 lots lol but after that it was always high enough :)
50% is defo too high mate, atm I'm paying between 5-10% still a lot but better than not being able to buy at all! Once I got lucky and paid near enough no extra markup. I find midday to early evening gets me the best price usually.
It's worked well for me since April, think I'm getting close to that 1200 limit though haha good luck with it bud