Buying a new guitar for $50 or less is not going to give you an instrument that will be enjoyable to play. It will likely not stay in tune, and it may have intonation problems, so your chords will sound all wrong, too.
Spending in the $100-150 (or 160) range for a decent new guitar will get you something enjoyable that will also last.
The F335 mentioned above is a worthwhile option.
Another way to go is buying a used guitar, where you can get the same level guitar for under $100.
But new guitar for $50? I beg you not to.
Even for a beginner - it's hard to enjoy an instrument if it's difficult/impossible to play music on it.