I'm assuming you want to sharpen your own knives and not pay someone else to do it. It's not that hard and you don't need a lot of expensive equpment to do it. We teach Tenderfoot Scouts to do a decent job of it all the time. Are they perfect? No. Do they learn well enough to have reliable blades? Yes.
So, go to Lowe's or Home Depot or any Walmart, anywhere they sell a decent array of tools. Find a stone that has coarse grit on one side, a finer grit on the other side. Get a small container of sharpening oil; ought to be sold with the stone or right next to it. Then, watch any one of a number of videos on YouTube that tell you how to use that stone.
If you get diamond stones, you can forgo the oil and use water instead -- so I'm told. Never used them myself, but people I trust like them a lot, so I am mentioning them.
This may not be exactly what you want to hear, but it's a good idea to know how to sharpen by hand, eye and feel. You will have a much better appreciation for the craft.
Then, when you are consistently turning out a decent edge this way (buy a bunch of cheap used kitchen knives at Goodwill to practice on, so you are not grinding down your favorite blade all the time!), consider this:
Lansky Sharpening System
I'm giving you the link to the manufactuer's website, but you can get them used or new for just a few bucks on Ebay -- I got my kit from a soldier returning from Iraq who was trying to cut down on all the gear he had to ship. Felt pretty good about sending him the bucks and making his life a little easier. My set has coarse, medium, fine, and ceramic stones, plus a ceramic V-shaped stone for serrated edges. I strop the knives on the inside of an old leather belt and have a very sharp edge that lasts.
There are likely to be folks who will pooh-pooh the Lansky system. Yes, there are better sets. Maybe someday you and I will move up to them. But dollar-for-dollar, you can get a darn good edge with a Lansky set.