a budgeted setup for a proper calcium reactor is, give or take $1000 unless you can find everything you need second-hand.
ill give you a list of what you need
CO2 tank - $100 - $200
CO2 Regulator
$150 low end $300 High end
Kamoer STP doser $300 (high end)
Calcium reactor for 200 gallon $400...
Raffles have a lot of laws and rules attached to them. I think they are almost classified as gambling so they, fall into extreme grey areas of the law. that's why a lot of the Instagrams or facebook raffles are done very down low.