Can a text be considered a legally binding contract?

A text can be a legally sufficientl writing to create a contract.  Indeed, most contracts do not have to be in writing to be enforced, although obviously oral contracts are harder to proved.  Although you may not have believed you had a contract until and unless you got a signed quote, you did not indicate that in your ocmmunicaitons.  If you had texted something like "subject to my receiving a signed quote", you would be in a better position. However, your position is still probably pretty good.  The question here is whether  a contract was ever formed when a price was never agreed upon; usually price is a fundamental term without which a contract can't be formed, but in some instances, for example where there is a course of dealing or a set price in the industry, a contract can be formed even though the parties never explicitly agreed on a price.  The other question is what, if any, damages the other party suffered due to your breach (if it was a breach).  If he/she had time to replace you, and paid a standard price to do so, there may be none,and you would have little exposure even if you are deemd to have breached.