The wife wants to visit San Diego in about a month to see Balboa Park,  the Zoo, The Midway, etc.  Any recommendations on where to stay that won't break the bank?  We are planning on driving too so need parking and of course somewhere safe. Somewhere by the park or the beach would be cool as we might just take Uber to places we want to go to not have to try and park everywhere. I looked at Hotel Coronado but that is $550 a night  Thanks

A place we've stayed and enjoyed ourselves - Hyatt Regency Mission Bay.  

The rooms are clean and neat and large. They have restaurants and a great set of pools and slides.

That is Mission Bay in the background.  You can rent jet skis at the dock and tool around Mission Bay.  

SeaWorld is just out of the frame, off to the right (almost walkable).

Midway and San Diego Zoo require driving or a taxi.  

We live not much over 90 minutes away up (the) I15 so seldom stay in the San Diego area.   Stayed a couple of times in the Escondido area to be close to the Safari Park - it's free to seniors 65+ in February.  Up there I'd go again with the Holiday Inn Express and Suites (a Comfort Inn next door at essentially same price).  The sub $100 chains for the most part are not recommendable, sketchy neighborhood, rehomed in the motels, homeless wandering the areas, etc.

If there's an HI Express & Suites in the "area," you can price compare for an idea of price/features range, at least.  

San Diego has several vacation/resort destination areas which might be pricier than desired or maybe you'd like the extra atmosphere and amenities?  

Like Mission Bay, as the one pointed out.  San Diego Bay front or across the street from the embarcadero, or "Islands," convention center adjacent may be up range price wise.   I don't think finding parking is a problem at most places but I'd check the listings with Travelocity, etc., to see if it's free.  some of the nicer areas have adjacent shopping, entertainment, convention/parking structures so pay parking wouldn't be a surprise.

Near the airport is not inviting, you aren't flying in or out? the area had some pedestrian activity as I passed through from a fish place Sunday night (the one I wanted was closed, I guess if not a sports bar, restaurants fall off the radar on super bowl Sunday).  So maybe gentrifying a bit but not sure much of San Diego is stroll with the wife territory these days.

There's "Hotel Circle" in Mission Valley.  Pretty close in, traditional vacation stay if not as full on resorty as the water side spots.

I've not used Uber, etc.  Might be a thing to consider.  There's a lot of tourist activity in the area of the Midway so pricing may be available but will likely be "pay."  They may have recommendations or some of their own.