Look up you local building codes. Even if you do it yourself, you may need a permit and have it inspected. I'm assuming the sump pump is in your basement or otherwise relate to a dwelling, not just in the yard for something. If you don't do it right per code you risk some nasty consequences. You don't want water backing up and flooding or seeping under you foundations, etc. You may eed to install a back flow preventer. Depending on the local codes and purpose for the pump, it may need to be connected to sewer or surface water drain lines. Something like this is not worth the risk of trying to circumvent codes to do it on the cheap. At the very least, I would get a couple of contractors to look at it and give you estimates and have them tell you exactly how they would do it and why.