The quality of an audio recording is limited only by it's weakest link. Be that microphone, pre-amp, monitoring, artist skill, mixing skills, etc. It's not always the equipment that is the weakest link...
$300 is the BARE minimum you should spend on EITHER a mic OR a pre-amp/audio interface for a decent quality recording. Not both.
So to expect to get good quality with only $300 spent between them is not a good look.
Look at one item at a time, and how it's going to work into your setup both now AND in the future. There's no reason to upgrade now only to realize you have to upgrade both pieces again in the near future.
Like foggy said, save your money and look at 2 pieces of quality gear that will do what you want now and not hold you back in the future. Also, tell us WHAT you are recording, and HOW you are doing it. What is your process for recording?
You might look up FP member Morning_Star and look through his posts. He is constantly making suggestions for people with similar needs to yours but with low budgets. The thing is, you gotta learn and decide what you need now and what you want to do in the future to make a good choice.