What should I do before buying HTP service?

You don’t need to do the htpq unless you want a life root (required for bishops to get genesis). Else, just get the medicine for transformation and you’ll be fine
A regular htp+egg combo will cost you about 35m and 1.5 hrs of runtime

 

to be able to get inside ht cave u need this use item called dragon elixir, it's from the secret medicine quest so ur on the right path. U don't really needa do the certificate quest as it is for people to get inside the second map in cave without having to do the htpq. Min level is 120 to be able to take the medicine quest and get inside cave, as for the price it may vary depends on the seller, u can check out free market in ml discord. GLGL

edited: oo ya thx for the correction, its 80 lvl to get the quest

 

Level 80 is required ~> https://bbb.hidden-street.net/quest/leafre/wars-of-the-dragons

 

Ht hits 7.8k max if your party knows what it’s doing, 9.8k if it doesn’t. If you’re a mage you’ll be fine, but beware that HT dispels, causing your magic guard to disappear

 

Yes you can do it after level 80, but the htp is lvl 120 to wear it