thats a stretch...
$50 is basically the lower end cases (either bad air flow or no extra's like rbg)
$75-100 is gonna be likely the min for a decent RBG case with proper airflow
could always check sites like amazon, newegg, etc for sales/deals on cases (i got my EVGA DG-73 which is normally $80-90 for $40 on sale...oddly enoguh havent had any air issue that some report with it) just might take awhile to find one you like.
also depending on the components you might wanan try for a larger mid-sized to full case (if u have large/bunch of stuff inside smaller cases will turn into hotboxes even with good airflow normally)