As I really suck at leveling a guild and obtaining members to do so (tried a bot to invite random people) I'm basically leveling my guild by myself. So my next option is just to buy a guild that is at least at level 20 - 25. I don't know how much they go for, but I don't care about what achievements, guild tabs etc. Just the level. If its cheaper just to buy a guild without much going for it (as in guild tabs, achievements etc.) then I'll take it.
Also, the seller has to be willing to give up the guild first before any trading happens. I do not feel like being scammed