The general idea is that one can purchase rod stock cut to 7 inch lengths, nails, bolts etc., wrap the ends with Cordura, suede or leather, and then bend them so the ends are less than 2 inches apart.
The process is the kink, sweep and crush.
Progression from 1/8" - over 3/8" rod stock. People bend timber nails, 20 penny nails and 60 penny nails.
There is quite a bit of technique involved and surprise, surprise you can hurt your hands.
Eat Chalk Get Big sells starter kits
FBBC sells leather wraps
Ironmind makes cordura pads that are also sold through Cannon Powerworks.
Shortsteelbending.com also sells steel at reasonable prices and they have great reviews. I will definitely be getting the free beginners kit which includes cordura wraps, 6 bars of steel and a beginners guide.
Suggestions also include buying:
20D nails (0.192 x 4") - $6 for 1# (28 pieces)
40D nails (0.200 x 5") - $0.20 each at Home Depot
Timber ties are another suggestion (1/4 x 6", but effectively less than 0.250 due to twist) - $35 for a 10# box at Lowes
1/8" x 4 foot - CRS - $3.98 - Lowes
3/16" x 4 foot - CRS - $4.98 - Lowes
1/4" x 4 foot - CRS - $5.68 - Lowes
I will probably end up buying a cut off wheel and grinding wheel for my angle grinder. They do not seem too expensive. Around $5/wheel (Harbor Freight). The expensive item will be a vice which I have wanted for a while ($50-$100 at Harbor Freight). The vices seem to hold their value with nothing particularly cheap on Facebook Marketplace.