Step 1: Identify the character.
The rattrap seller was a homeless, wandering vagabond who lived by begging and selling rattraps.
Step 2: His work.
He collected scraps of wire that he found or received as charity.
Step 3: Making of rattraps.
He bent and twisted these wires into small traps that were used to catch rats.
Step 4: Conclusion.
Thus, his livelihood depended on making and selling rattraps.
Final Answer: \[ \boxed{\text{The vagabond made rattraps by twisting scrap wires.}} \]