Guybrush Threepwood

Second what birdhouse said. Mega Plaza Wangburapa in China Town. It can't get geekier, this place is on a par with Akihabara.

https://www.google.co.th/maps/place/Mega+Plaza+Wangburapa/@13.7472506,100.4976355,15.5z/

I wanted to try Uber and Grab but both of them quoted quite a high price. Eg from Phloenchit to DMK the Grab app quoted 450 THB before booking. The usual taxi price with meter is about 200-250. Same with Uber: from MBK to Cenral Embassy the Uber app quoted 170 THB. Is it normal that Grab and Uber charge so much?

Does anybody know a shop in Bangkok where I can rent music instruments like electronic keyboards? I've checked already the known music shops around Thief Market, Wat Tuek, Atsadang Road, Central World, Siam Paragon (Yamaha Music School) but nobody rents instruments. Any further ideas where to look?