labor isn't cheap and this is an easy job. i found out some fitting the previous owners had rigged up rusted out. i disconnected my sump pump at a fernco and pulled it out by the pvc pipe and it was literally hanging by the cord at that point. i ended up replacing it during a rain storm and it took less than 15 minutes. i got the older version of this which came with preinstalled check valves. i also got the recommended battery and case for it. https://www.amazon.com/Wayne-WSS30V-Upgraded-Combination-12-Volt/dp/B07H4S6X9N/ref=sr_1_1?crid=1E96I6VDCRGMO&dchild=1&keywords=wayne%2Bcombination%2Bsump%2Bpump&qid=1611032849&sprefix=wayne%2Bcombin%2Caps%2C200&sr=8-1&th=1 apparently this one doesn't come with a check valve though.
This is the stump pump I bought; the pump and the battery backup are all in one, and the backup is the same quality as the main pump. It's more expensive then when I bought it, but I've been very happy with it.