Buying clothing for work is tricky because you always want to look your best and follow trends. Here is some advice to buy clothing when you are on a budget. Your budget for clothing shouldn't be more than 5% of your income after tax. If you're income is $2,400 a month, then your monthly budget on clothes should be $120 a month. If you're building your working wardrobe from scratch you can allow yourself to use 7% of your income.
Try to get good basics, like black pants, button-downs, versatiles cardigan and neutral color tees. When buying a suit... a good quality suit can go up to $1,000. But you can find very good suits at $250/$300.
The key is to invest in quality so that your basics last for a very long time. But let's be honest, it's best if you don't go in debt for clothing. Add new apparel as you go. Little by little you will have a great wardrobe!