Back in the 60's my dad installed a sump pump pit. The pump was below water but the motor was installed above the pit on a long shaft .
Today we normally use a basin, like this one. It is a 22 gallon Polyethylene basin. They come in both vented and non-vented, check local codes. A vented style goes to a vent on your roof.
I personally like the Zoller family of pumps, as they are cast iron and they take a beeting. Please dont buy a pump with the integeral floats., as you can not adjust the water level for optimal perfomance. So what are you going to use as a float? There are two solutions: