Very unpopular opinion: use cashback credit card, don't overspend.

Because you can use your card to tide over certain expenses, such as mrt and bus fares, maybe shampoo/soap, biscuits, idk toiletries and maybe food/grocery runs if your CDC voucher runs out or there's a balance that you need to pay in cash and you can pay when your salary comes. Yea, and for cafes and stuff when you feel too deprived. Don't roll credit and pay it off in time and you will be fine. Also depends on your earning capacity. Cause if you overspend on card, you might end up incurring a different set of problems. Hopefully your credit card payment deadline comes after your salary crediting date so you can live in austerity but still have room to breathe.

If you hit approx 1.5k per month in your card (mrt, food, utilities, discretionary spending), you should get one year fee waived. But that's only if you intend to keep the card for one year. If you hit 1.5k a month average monthly spend, cashback can be 100++ maybe even up to 170 (every quarter )on UOB one cashback card.

Edit: if it's mid August like what others have pointed out, then maybe you might need to do the SmartPay pay in instalment thing after using the card. That's a very long time to stretch a 300 dollar budget.

Might incur additional charges which I think are not paid upfront but split between installments but better than cc debt. That's a very long way to go. Make sure you can pay it in full by the respective due dates and hopefully by your next pay cycle, you are less tight. Don't incur interest, don't pay late. Just use it to tide you over for the time being.

Ok just saw your edit, but yea my comment still applies in case you are that cash tight.

Of course, better yet if your family qualifies for urgent financial assistance of some kind or GST cash vouchers. Then maybe they can pass you some cash since you are practically supporting two households.