There's no such thing as an inexpensive M14. You have 2 options:
1. Buy a quality one such as TM (preferably) or CA and have a completely working package out of the box with no foolery required.
2. Buy a "cheap" one, then spend the next 6 months replacing parts as they break. Once you've got completely new internals and externals, you'll have nothing left of the original gun left but the stock and receiver and will have paid more for it than for a TM.
I've become a big fan of the Chinese clones such as A&K and JG for many of their guns such as ARs, AKs, MP5s, etc. They've made huge strides in quality and durability in the last years. I've wholeheartedly recommended them to many people. But honestly, every clone M14 I've had contact with sucks ass to the highest dregree. They're unreliable, break easily, and in the end, cost far more than a quality gun would in the first place.
And even the CA (and I'm a HUGE fan of CA guns) doesn't hold a candle to the TM (and I don't usually care for TM guns). Don't waste your money.