Fixington lets you record payments against the work. The invoice and the money sit together, so you can tell what has come in before you start another job.
Example
Cash, a transfer, a card machine you already use: note it on the job when it happens. You are not keeping a second list of who has paid, and you are not trying to remember on Friday.
The point is to leave the drive knowing the invoice is out and the payment is written down.
Open the list and you can see which jobs are still waiting. That is the cashflow view most one-person trades actually need: not a ledger, a clear note of what is outstanding.
Payments stay on the account with the invoice, on iPhone, iPad and the web app, so the record is there when you sit down to chase or to tally the week.