No, you can't buy a reasonable quality wheelchair for less. You can buy what a person who doesn't need a wheelchair consider reasonable. If you had to use those cheap chairs for 16 hours a day, and pushing yourself even just for a mile of well paved roads, not even uphill, you would never consider those reasonable.
Except the wheelchairs used in hospitals are to push patients short distances across hard flat floors.
This is absolutely the point. You have to live sitting in there. That must be more comfortable than the best thing in your house. No way you can do it for less than 1k.