Well there isn’t one, sorry to say that but the cheap protein powders are not as effective by any means as the more expensive ones and cutting costs and indeed corners will get you nowhere, saying that though if you simply cannot afford to get the best then get the best protein powder you can afford as you will see the benefits. All the cheap protein powders are just that, cheap they don’t have any of the added ingredients you take for granted in the higher end ones, such as creatine, caffeine, nitric oxide or any other added extras to help you along your way. My advice would always be to go with whey protein as this is the best kind of protein you can get your hands on.
Whey is the by product of cheese production and has many complex amino acids and globular proteins. So what does that mean, well it means that the protein is absorbed into the body up to ten times quicker than normal protein which is great especially as i then makes perfect sense to use it as soon as you are finished at the gym, that way you can get good quality protein to your muscles that need it within several minutes of finishing your gruelling workout. So for me the best cheap protein powder is going to be the best whey protein powder you can afford to buy.
Unfortunately you could possibly do with extra products such as nitric oxide supplements as this will speed up the muscle building process but you have to make do with whatever you can afford right!. I personally would make do with just chicken and other high quality food sources and save up your cash and then buy in bulk the best protein you Can get for the money as buying bulk will save you a hell of a lot of money.Good luck.