Re: That Trike...
You asked for suggestions for a low cost fork set. I like moped forks for several reasons. One, they stretch the bike out a bit, giving a longer footprint. They make for a more comfortable ride and the suspension should help cornering a little. A used fork is priced right. If you go that route, check the diameter of the head tube which is probably 1". Fork and head tube need to match, although you can get an adapter to use a 1" fork in a 1 1'8 head tube. Also check the length of the head tube and look for a fork that is long enough. A little too long you can make up with shims. I've used Tomos, Hercules, light Harley Davidson and Suzuki K-10 forks. I'll never go back to rigid forks. I also like it that the moped forks are usually set up with ears for mounting a substantial headlight. Yes, you can mount a 26" wheel in a moped fork.
Someday when I grow up I will probably lose interest in toys with wheels, but until then...