refreshes every what, 1 or 2 days? 
I just circulate. Hit up Riften, sell all I can for the 4k Tonilia has. Move to Whiterun, clean out the fence in the brewery. On to Markarth. On to Solitude. On to Windhelm. Back to Riften. 
Takes forever to sell everything. I sell soooo much. most gems. most potions. then I enchant weapons and jewelry and clothing and sell those. So, seriously. I sell sooo much shit.