Well, depends on your budget, class, level and damage output.
If you're decked out and dish heavy damage, you can invest in leech gear that can nullify pot usage altogether. A +10 EDA (1.5b at most) is already a great investment. Add the new Catharina Von Blood (2b) with a Succubus Pet (250m) and you're set honestly. Also, the Malicious Set (200m per piece at +0; 3 pieces [armor, shield and boots]) can help a bunch. Hunter Fly cards (90m) always are an option. Depending on your class gears, you can choose a combination of these. Toy Syringe (300-400m) is super good too, to use the less pots as possible when leech RNG isn't on your side or your mob is too big Thanatos weapons (price varies on type) after level 120 are super efficient.
If you're damage isn't too high, leech will become less efficient. Healing boosting cards and gears are the way to go sometimes, especially the early levels as some have stated. Aloe Leaflets (like 2.5k each) are a nice alternative up until level 110. I used them quite a lot. Flamel carded (60-70m) garment can be a cheaper alternative from Toy Syringe, though, that means no Raydric or Deviling. Toy Syringe is definitely the better one for most scenarios as lower headgear slot is not as vital.
From experience, I would invest in a +10 EDA and a Toy Syringe first. The leech and efficiency increase will make your life easier for the less amount of money (even though it's still quite high), and that combo is the most friendly to most classes . Catharina and Succubus Pet could be a better alternative if your class doesn't need the Upper Headgear slot that bad. Analyze your classes and plan accordingly. Gens for example, usually use Cylinder Headband for leveling, so EDA would be better. GXes on the other hand, don't have a vital need for upper HG, so Catharina is better (though, GXes can as easily wear EDA).
If you don't have 2b to spare, Hunter Fly cards on a Crimson/Thanatos Weapon with a Succubus/Incubus pet are super good. The Malicious Shadow Set greatly improves any budget set too! Also, there are new cards out there that I probably can be missing because I just returned XD Also, don't forget +9 Ride Word Hat (450m) and it's less popular sister +9 Cursed Hat (450m) still exist!
Bottom line is, the better your damage and the more leech you have, the less pots you'll use. The higher your level, the better it gets, even with budget sets.