underbuy

verb

1. (transitive)To buy at less than the value of.
2. (transitive)To buy at less than the price of another.
3. (ambitransitive)To buy too little.

   “Well, just as you can overbuy when selecting a home, you can underbuy. That's what Nathan and Rebecca did when they bought their first home. They believed in living within their means — a good thing — but they took it to an extreme.”