We compare one sinis game right now: Wandering Gem Jockeying, at NZ$5.19 (Steam).
Right now we have in-stock offers for sinis games from G2A, Kinguin and Steam.
Not always. Stores that sell their own keys, such as Steam and GOG, add no service fee, though sales tax is added at checkout in the US and Canada. Marketplaces add a service fee at checkout, and some payment methods add their own, so on a marketplace the total at checkout will be higher than the price listed here.