i Don’t know if the OP will see this or not, the thread is rather old. Here goes. Don’t buy a truck. Period. You’ll be throwing your money away, as has previously been posted. Find yourself a trustworthy agent, and invest your 40k in a good growth stock mutual fund. Something that exceeds the S&P 500. Keep working your regular job(s) and keep saving.
Buy about 3-4 trailers where you can rent them out at 500 a month easily.. Pay about 4-5 k for each one. Put about 3-4 in each for rehab.. once rehab you can easily rent them or sale them to someone as a rent to own deal or outright cash.