Hey Darth! Do you have any specific blocks in mind? Or blocks that you would not consider due to them not being worth placing? Do you have any per block prices in mind? I am not a great "mathemetizer" but I have found out that 25 gold blocks = 15 levels pretty much exactly. With that I am still not entirely sure how many it would take to make 4k levels. I would math it out but have to get some sleep since tomorrow is a "grampa day" and I will not be back on til later in the afternoon.
I believe that @MinecraftParkerH is selling me some iron blocks for 4k levels but I will get back to you if that changes
Scratch that last post he can not supply the amount of blocks I need @AdmiralD, I am willing to pay 400k for 4000 levels worth of blocks.