OK that makes sense. Given that the amount is $300, I want to ask if it is possible to sell anything of value to raise the cash? This would be preferred to getting a loan, since many short-notice loans can carry high rates of interest.
There are lower cost alternatives though. Credit unions often have some of the lowest rates for people that have average credit.
Your situation reminds me of another local client that was facing a similar scenario. I hope that the suggestions that we offered her can be of some help to you also.
One last thing you may try is peer lending, since those investors offer small loans that can be commonly lumped into the $300 that you need to cover your security deposit.
One word of caution: stay away from the payday loans. Those predatory products are common in Dallas and carry ridiculously high interest rates. They are a common stop for people looking for a small amount like you are, but they become a big mistake for most borrowers.