I strongly suggest doing your home work before acquiring any CO2 regulator, research the benefits of dual stage vs single stage, needle valves.
cheap as in most cases can be costly & frustrating in the long run.
Almost all the commercial plug and play co2 regs. have actual users reviews/ experience with them, apart from google , The Planted Tank Forum - Powered by vBulletin has a ton of threads on various regulators & more.
Personally it`s one area i try not to cheap out on.