You never really told us exactly what you do, what kind of shoes are appropriate for your work, the exact type of shoes you are currently wearing for work, whether you are male or female, etc etc - so this advice might be totally off base. You said you buy "nurses dress shoes", and when I search that in google I basically get clogs.
If you are a nurse and are always on your feet, then going through a few pairs of $50 shoes a year may simply be a cost of doing business. You don't want to destroy your feet / back so $150 a year to keep you comfortable and presentable is probably not a bad expenditure.
Or perhaps they make more expensive shoes that are appropriate for your line of work and will hold up better. Personally, I work in an office and wear Allen Edmonds dress shoes. They are expensive, but hold up well and look great (which is important for my job). The trick I found for them is to buy 4-5 pairs and then rotate them. This way I only wear a single pair once a week or so. I also use shoe trees and clean and polish them regularly.
So ultimately my advice would be to consider a higher quality shoe, and then consider buying several pairs and rotating them. The up front cost can be considerable, but you will likely get much more life out of the shoes this way than if you simply buy cheap shoes and then wear the same pair day in and day out.