purchases – repairs – sell

What I would do is the next:
1. For each part or bicycle you make purchases of, create an expense (it doesn't matter whether you make all your purchases at once or in several instalments, as long as the unit price at the time of purchase is clear).
2. Create sales items:
working hours
each part separately
3. Create a sale (it doesn't matter whether it's to a private person or on invoice) and include all relevant parts:
- each part x amount x unit price
- working hours x amount x hourly rate
Dexter will then calculate what is stated on the sale (invoice).

Johan

Thank you. Then I will add to the previous example:

Purchases:

Bicycle 50 euro, brakes 5 euro, tyres 10 euro, working hours 1x 5 euro.

Sale:

Bicycle 200 euro.

Or should I add the parts and labour hours to the sale? In that case, the sale price would be 220 euros? But then it wouldn't be correct.

I can't put 180 euros for the bicycle and then add the parts + labour hours, because then the private person would say it's not correct because she would only have to pay 180 euros.

You have to distinguish between the purchase price from the bicycle and the parts and the selling price. There is nothing wrong with making a profit on the parts or the bicycle itself (the customer just doesn't need to know how much). So when selling, you should put something like the next:

Second-hand bicycle for inspection: unit price £140, amount 1, total: £140</

Brakes: unit price £10, amount 2, total: £20

Tyres: unit price £20, amount 2, total £40

Total = £200.

This allows you to later check in Dexxter where you earn the most (parts, the bicycles themselves or the working hours).

I would not include the working hours (but only charge them when people have their own bicycles repaired). Your working hours are very cheap, usually between 30 and 50 per hour. You can then select whether to charge for the entire hour or per half hour started.