My pool is a bit bigger and I use one 3 jug case of Clorox per week in the heat of the summer. I add 1 big 182 oz jug of 6% bleach every other day (or 5.2 gallons per week). Cost about $8. I have recently switched to 10% Liquid Shock from the pool store and it seems that I am using less on a dollar cost basis, I have not been back from vacation long enough to be certain. Once temperatures are less than 95 - 100 degrees, the chlorine usage goes down.
However, your pool will be different. How different will depend on all sorts of things; first the level of stabilizer in the pool now, whether you have some algae now, how much sunlight, agitation (fountains, waterfalls, cannonballs, etc), swimmers, whether they lather on the sunscreen and hair products, if they shower first, dogs in pool, how clean you keep the skimmers and floor of the pool...... all this and more play into chlorine usage. I have a medium-high agitation from spillover spa, low usage, high leaf and dirt levels from trees and landscape, sun but a lot of shade as well.
I will point out that I also do use trichlor tablets from time to time, when I go on vacation. Because that adds stabilizer (CYA) I am very careful about how much I use of that. Only when CYA is at the low end of the range. Never when it is above 45 ppm. I also use cal-hypo from time to time, when my CH is low. It is even cheaper than bleach, if you need the CH. Trichlor is cheaper than bleach, if you need the CYA. Liquid Shock is a bit cheaper than bleach, if your pool store carries it at a good price. Bleach is cheaper than all of the above if you do not need the CH or the CYA because by avoiding the build up of CYA you avoid having to drain and refill the pool and add back the correct chemicals to balance it (maybe CH, maybe metals from well water, maybe acid to correct pH and TA issues). Most of all, if you keep the CYA and the chlorine in line, you avoid things like Clarifiers, 'algae destroyers', flocculants, and all the other junk the pool store seems to want to throw at pool owners.