So that Target trip is probably one trip, but where you might put the two amounts in different columns, one for grocery and one for clothing, this approach splits it into two lines.
Then, if you want to look at totals by category, for example, you can use a pivot table. (Contrary to @MacSparky’s recent digression, pivot tables can be very useful in making sense of data like this.)
All that said, if a column per category works for you, keep doing it!
I would just set up a pivot table in another sheet of the workbook, with ranges that include not only existing data but also blank cells that will hold future data (eg, in Google Sheets: A1:C will get all cells in rows A to C, however many rows there are; pretty sure the same works in Excel).
Then as I add data, the pivot table will update, eg with totals. In fact, as I add new categories, the pivot table will expand to include them.
To avoid accidental categories (the “grocery”/“groceries” problem), I would do two things: one, rely on auto fill once I’ve used a category once; and two, have a master list in a column in a tab (usually named lookup), and use Data Validation to flag values that aren’t in that column – ideally with a drop-down list for when I don’t want to type. But this is optional, since the pivot table will show you quickly when you have stray categories (suddenly there will be a row for grocery and groceries).