What two words best describe these features?

Question

I am in the middle of developing an app. I'm having some trouble trying to decide the best usage for two features in particular. I know what both of these words mean, but I am becoming increasingly confused and irritated the more I try to find a good-fitting word for both features that is not only easily understood by your average Joe, but also doesn't sound too weird or out of place.

Expense and Purchase.

The reason I am becoming confused is because I was originally using the word Expense to allow you to enter things like Grocery Shopping items, utility bills, petrol, lunch, dinners, etc.

But then I wanted to make things a little easier. I wanted to separate necessities, or things that we really need from things that we want - or just simply one-off purchases. So then I introduced the word Purchase. So now I have a menu that looks like this:

File ---New ------Purchase ------Expense ...

You click on New Purchase if you've just bought something and want to record it (this is a budgeting app). You click on New Expense if you have things to pay for like bills, petrol etc on a regular basis.

I'm not sure anymore. I've confused the heck out of myself and now I need some help.

Which word would best describe the feature: "I just purchased something and need a record the details of this transaction" (Please don't suggest using the actual word Transaction. That word is literally everywhere else.)? And which word would best describe this feature: "I have some bills and/or items that I buy on a regular basis, and I want to record the details of these future transactions."?

Remember: I'm trying to keep them separate. I know I could just use one word for both features, but due to many minor differences in each feature it could be confusing to others and I like a nice and clean interface.

Answer 1

Generally, questions related to programming are off-topic here, and you'll get better answers over at the Usability Stack Exchange, but I'll take a stab:

From a usability perspective, the user shouldn't have to interpret the meaning of these labels. They should be obvious.

If I were you, I would think about labeling them with more than one word to make it crystal clear. Something like:

File
---New
------One-Time Purchase
------Recurring Expense
...

Answer 2

@Kevin Workman's suggestion is excellent for the coding part.

As to the English question: An expense is something that happens when you make a purchase. You purchase an item or service, meaning you must give out money. The expense is an aspect of the purchase. The item or service purchased comes in. The expense goes out.

The confusion may arise because you are thinking of purchase as only those cases where you get some object. The object purchased is the purchase. You bring home a bag of hammers or a loaf of electrical wiring, and that thing is your purchase.

But services, such as electrical service etc., are also purchases. You purchase your water supply, your taxi service, etc. You pay out the expense.

So the purchase should be the item or service purchased. The expense should be part of the purchase, the amount of money you pay out for that purchase.