Sabian AA and AAX cymbals are the same price. As is HH and HHX are the same price. Both AA and HH series are considered Professional quality cymbals. The design, materials and lathing are the same in AA to HH and AAX to HHX the difference in costs come with HH being "Hand Hammered." It's a time consuming procedure and the end result is there are more uneven harmonic overtones in a hammered cymbal. This makes them sound trashier or complex but not necessarily better. AA and AAX are great for power and projection as well as an even tone in your cymbals. This is why the rock n' rollers in Sabians endorsers use these cymbals. Sabian is as good as any cymbal company in the world.
Zildjians are slightly different but of the exact same material, go through similar lathing but the difference is in their design and their hammering process. Their K series is hammered by machine. K's would compare to HH and the regular Avidies would compare to AA/AAX. The final differences are subjective. Zildjians are of the same tonal quality as Sabian, just different.
The difference is in the attack of the cymbals. Although weight is the main culprit for determining attack, the contour of the cymbal is what sets the two companies apart. Zildjian looks like this } and Sabian looks like this ). The end result is Zildjians have an aggressive attack when you strike them to open. Sabian has a smooth or swelling effect when you open them.
For cost efficiency, I'd say either choice of Sabian or Zildjian are wise choices. You could also consider Stagg and Dream cymbals which are made using Turkish and Chinese methods and are cheaper but are not as durable. Sabian and Zildjian both offer 2 year warranties, the longest any company offers.