Check prices on eBay… quite reasonable for used/refurbished Dell laptops…
I’ve had excellent service/performance running linux for 8+ years on several Dell E6500s, 8GB, core 2 duo, 15.6". Price on eBay today $75, $12.72 shipping.
Also run linux with excellent service/performance on an E6420 with 8GB, 14", E6530 & E6540, both with16GB, 4 core, 15.6".
An 8GB, 14", E6420 can be bought, including shipping, for less than $50
Excluding the E6420, all the systems I’m using have DVD R/W drives and backlit keyboards.
Haven’t had any driver or other problems with any of the systems running linux.