When extra costs come up in the course of your work, you shouldn’t be left out of pocket.
Your employer probably has an expenses policy, which will help you understand what you can claim.
Common examples include travel expenses if you have to go somewhere other than your usual workplace, mileage if you drive for your work, or hotel accommodation if you’re away from home for work purposes.
You should follow the expenses policy very carefully, because any breach can have serious consequences, possibly including dismissal.
Resolving expenses disputes can be stressful and time-consuming, so it’s best for both employers and workers to have a clear policy so that everyone knows what the rules are.
If your employer doesn’t have this kind of policy, consider getting the support of colleagues, or your union rep, and asking for one to be developed.