It is unwise to pay too much, but it is worse to pay too little. When you pay too much you loose a little money. That is all. When you pay too little you sometimes loose everything, because the thing you bought was incapable of doing the thing it was bought to do!

The common sense law of business balance prohibits paying a little and getting a lot. It cannot be done!
If you deal with the lowest bidder, it is well worth adding something for the risk you run; And if you do that, you will have enough to pay for something better.

If you pay for a cheap roof you will get a “cheap” roof.
If you pay for a quality roof you will have paid for worry free protection.
And really it is always more cost effective to do it right the first time