Calamus (Acorus Calamus) is a very cheap, easy to come by herb (at least here in the Netherlands for me being quite fascinated by herbs and having sought and found some herbal suppliers and stores).

Alot of Smartstores sell it, but I bet the local herbalist, selling dried herbs, has it too. I know a nearby herbstore sells it.

What caught my eye was the serious, repeated experimenting of this person and his/her mentioning of how, time and time again, it proved to potentiate dreaming incredibly and even induce one LD:
http://www.erowid.org/experiences/exp.php?ID=44156

Worth a try perhaps? Since an ounce of this Herb is a 10 minute train-ride, a 10 minute walk and only €2,50 away from me I'm thinking of getting it soon.

Anyone care to participate in this experiment with me?