I've purchased stuff from Menards (box cars in multiple packs) and quality has been reasonable. Lionel sells 6 packs of certain types of rolling stock and time to time Amazon will sell them at a discount. I just bought a 6 pack of gondola cars and the cost was reasonably discounted making them less expensive than Menards. All metal trucks with plastic bodies and operating couplers.
From time to time places like Trainland will discount Lionel engines and rolling stock-brand new stuff though sometimes not the most recent stuff.
John