Well... this will be my first D.I.Y. and probably not the last. If I think something can be made cheaper with my own hands I usually will. I'll add pics tomorrow afternoon but here's a list of what I used.
1 Axle
1/2"x18" cold roll bar $2.79
2 1/2"x18" sch 80 pv $3.98
Cut to 11" for axle tube and cross bar
2 1/2" collars with allen set screw $4.60
2 1/2"x8" sch 80 pv $2.18
For uprights from axle tube
2 1/2"x6 sch 80 pv $1.78 (+2 @ .68 cheaper)
For kayak supports
4 1/2" PVC tee fittings $1.16
2 5"x1" with 1/2"center wheels $5.98
______
Total so far.... $22.47
I was originally going to use the scupper holes but had to revise. To finalize I need 2 more 1/2"x6 sch 80 pv @ 1.78 and 2 feet of pipe insulation (hopefully less than a few dollars).
Final product tomorrow evening.
Added costs
2 1/2" pvc saddle clips for crossbar $1.70
2 more 1/2"x6 pv $1.10
6' pipe insulation $1.64
Final Total = $28.91 (I picked up the final items at Home Depot and prices were a bit cheaper

). Maybe I should have gone there first and saved a few bucks.
Final product...