If you shop around, u can easily find one around the same price as an RG now. 80RM Maybe even waaay cheaper.

actually.. RM80 is IMPOSSIBLE.. RM120 is still plausible, some shops have a lot of stock so they're clearing off for 120-130.. 80 is impossible, unless you're talking about not buying original bandai.. but even then 80 is a bit high

like AF Hobby is selling for 140 while Gwing is selling for 135.. i think if you shop around you may be able to get 130 or 125.. lowest possible is 120, i believe.. i do not think u can get 80 at all.. unless it's assembled

180 is retail price.. and no, you don't have to disassemble to transform.. it's just flipping out panels to reveal the inner psychoframe, no need to remove parts
if you have never tried gunpla before, i suggest you put off Unicorn until later.. the parts are slightly fragile due to transformation, and without adequate experience you may be prone to breaking certain parts.. just my opinion, you're more than welcome to try though, you'll find the kit quite fun and challenging to build