Aha! You see, the *cheap* way to do roasted seeds is as follows:

• Read back of "Positively Healthy" fennel & caraway mix tub to discover ingredients.
  
• Buy packets of raw sunflower, pumpkin, hemp, linseed, & sesame seeds. Also acquire fennel seed, caraway seed[0], cumin seed[1], rosemary & sage[2], & soy sauce[2], for seasoning.
  
• Get a nice big frying pan. Heat it up (no oil required). Chuck in the above - mostly sunflower & pumpkin, only a pinch of the seasoning-things. Roast for a bit, stirring around constantly, until things start going "pop" all over the place (a couple of min). Note: stand well back.
  
• Take pan off heat. Chuck in a hefty-ish splash of soy sauce. Stir around madly before it congeals entirely.
  
• Leave to cool. Decant into pot. Gromph.

This I think works out somewhere around a fiver for probably 3 or so pots' worth.

[0] Actually I have never bothered with this.
[1] Also good for curries & other stuff.
[2] All things you may well have already. I do, anyway.