Since it is easy for us to spend your money, I'd STRONGLY recommend getting the TF-Pro from the tftestkits.net link above. It has everything you need, and a really helpful magnetic stirrer that makes mixing stuff fun. Get the salt add on (I greatly prefer the drops version vs the strips) if you have a salt water chlorine generator (SWCG).
Download and install the PoolMath app to your phone. Use it to log the test results from the kit - it does all of the tracking and calculation for you for what to add. Plus if you need advice, you can link it to your user account here for us to look at. But that part is not critical, if you worry about sending data out to the wide world.
You know how to edit your signature - so add in the details of your pool there. Size, vinyl/plaster/other, make and models of equipment, features, etc. as others have done, so we don't have to repeat asking questions about those.
For a SWCG - I only have experience with my newish RJ-45+ from Circupool. Works well, and no issues. Their warranty applies even if you install it yourself - many others don't.
Easy to put in. I did need an electrician, but many do not. Use the search function here to find out what others have said about the various brands. Your other equipment, and whether you will have a pool guy install it, may tip the balance to a particular brand/model.