Yea I posted that 1-37 guide =) Glad it helped you out. As for the cost to get to 55, I continued with curse because it's so cheap and honestly not much slower than using teleports or something like that.
From 37-55 is about 5k curses, which is about 6 hours give or take (I believe at least 800 per hour is possible). Using the same method as for 1-37 buying runes by hopping around to me is worth the money you save. You can get body runes for 3-4 coins each because in port sarim a lot of worlds have the full 5000 runes available. As for water runes, getting 10k super cheap can be a bit more annoying as they are more popular AND you need twice as many of them. I bought a few thousand at 5-6 coins, then got a few more thousand at 7-8 coins, finally I picked up my last couple thousand for 9-10 coins each. I would say I averaged 8 coins per water rune which puts the cost of each spell at 20 coins which is about 100k for 55.