Big C south Pattaya, there is a boot inside next to the cashiers, very good guy Khun Anek and service, installation (at the parking lot) included in the product - did mine 2 years ago....
FES on Sukhumvit right at entrance/exit motorway 7
https://www.google.co.th/maps/place/บริษัท+เฟิสท์+อีสเทิร์น+ซัพพลาย+จำกัด/@12.9452393,100.9044889,21z/data=!4m6!3m5!1s0x3102be1d769d2b37:0xc1dee9e333377ad5!8m2!3d12.9452382!4d100.9043506!16s%2Fg%2F1tgnp2_5?hl=en&entry=ttu
yes 800 THB about standard price for taxi this route, Bolt should be 400-600 but not always available ex UTP, but if you gamble could be ok
AFAIK no bus/minibus service available
FYI - just paid the yearly property tax for my condo in Pattaya (not my reg. address and rented out) 486 THB for 69sqm, my house (company named) was 509 THB....so very reasonable