"I don't read a lot."
Translation:Yo no leo mucho.
Leer = to read (infinitive form). LWP = ( I ) read (in Spanish you don't always have to specify the person/ subject.
I think in this case it has to be leo because its still you doing (or not doing) the verb leer. I dont read = Yo no leo.
I tried "No leo tantos" and was marked wrong.
But Duo supplied a different alternative "Yo no leo bastante." Personally, I think "I don't read so much" is a lot closer to "I don't read a lot" than "I don't read enough.".