Answer:
1. Either none (if you have to buy a whole pound), or 1/4 of a pound
2. 3 whole pounds or 3 and 1/4 pounds
Explanation:
If $4 = 1 pound, then we know that $1 (which is 1/4 of $4), will let you by 1/4 pound of blueberries. Knowing this, we can simply:
Add up the one fourths
do 1/4 times $$
See how many times 4 goes into the number of dollars you have
Please correct me if I'm wrong :)