The reason I think the tablets are expensive is that they are just dietary supplements. If you want to increase the amount of 5-HTP in your diet, simply increase the amount of Tryptophan (one of the essential amino acids) in your diet..... Tryptophan is found in nearly everything we eat, but in high amounts in grains, poultry, dairy, etc. and that metabolises into 5-HTP.
http://en.wikipedia.org/wiki/Tryptophan
Scoffing down peanuts isnt a long term solution, but try a tin of rice pudding (rice and milk are high in tryptophan) before bedtime. On my last visit, ASDA had Ambrosia rice pudding on special offer, 50p a tin.
EDIT: here's another link.
http://nutritiondata.self.com/foods-000 ... 00000.html
I wonder if Inuit people suffer from insomnia as Sea Lion is super high in Tryptophan!!! Seems a bit of a carnivore's playground. If anyone's a vegetarian, then Soya, spinach, pulses and seeds are a good source of tryptophan. Don't forget to eat a good and varied diet as other vitamins and minerals are needed to metabolise tryptophan, like vit c, b vitamins, etc.