Cutting incidental expenses is usually the easiest…if you can actually track your spending in this category. This is because these tend to be either impulse or habit purchases such as the daily coffee, smokes, random snacks, newspaper or magazine, etc.
How much does that daily habit cost you? It’s easy to spend the money thoughtlessly since it’s only a small amount each time, but these small amounts can add up to big money over time.
Coffee: All labs should be equipped with a coffee machine. PI’s that expect insane levels of productivity will generally equip the lab (or at least their office) with a coffee machine to keep the caffeine running and the research energy levels high. Coffee is cheaper when you brew your own cup. If you don’t like the way your own brewed cup tastes, figure out how to make a better cup. If you can determine the exact growth conditions needed to trick that cell into doing what you want, you can figure out how to make coffee the way you like it.
Cigarettes: If you want to save money, kick the habit already. There are tons of health reasons why you should, and the price of this habit is only going up.
Newspapers/magazines: If you read your local newspaper religiously, then consider getting a subscription to it. Be sure to check if there are any student discounts. If you don’t, you should just stop buying something you probably won’t have time to read since you still have to read that one article for journal club, and the other dozen or so articles for your research project.
Random snacks: Stock up on these at Costco or the grocery store. Those little packages of chips or 100-cal packages of mini cookies are much cheaper when you buy them in bulk.