I though I'd add my 2-cents here what ever you guys or gals buy for a bike weather its ridged framed or not e-bay has front supenssion forks for sale for around $15.00 to $20.00 includes shipping. the problem is getting them to fit your bike.
Using the inner goose neck parts off a wreaked bike that will match your bike you can weld up a stem to fit the new fork to go on your bike its a little bit of work but I've done 3 and glad I did makes the bike very nice to ride.
Also changing out seats and handlebars makes big changes for the better. I better add that smooth treated tires will make the ride more enjoyable I inflate them to the max pressure.
I also like the foam handlebar grips that sell for about $2.00 to $4.00 the cheaper the better.
Ride it like you stole it!