I have been curling my hair this way. This, I think, is the cheapest way. If you have plenty of time, you can certainly do this.
When you hair is wet, part it two ways and twist it. Like this:
Keep twisting. When you are doing something, twist. When you are having breakfast, twist. When you are doing anything or whatever, twist.Twist until it dries. Then, voila, you'll have the cutest curls!
It works for hair that isn't stubborn, you know, that kind of hair who doesn't have its own mind or that kind of hair that "sumusunod sa gusto mo". This lasts longer on me.
• No need of fancy curling equipment
• Time consuming coz you need to twist the hair till it dries
• Doesn't work for all hair type, specially those kind of hair that is not easy to style and you need tons or hairspray to be able to keep the style last longer.
I hope this frugal tip on curling your hair works on you :)