Who this is not for
If your invoicing is a handful of documents a month to domestic clients, and Wave is available where you are, there is no argument here worth nine euros. Keep the free tool. A page that pretends otherwise is selling, not comparing.
Wave's availability and what is included have changed by country over the years, so check their site for yours rather than trusting a summary on someone else's page.
Scritta con cura e senza numeri sul prodotto altrui: prezzi e funzioni cambiano, quindi per quelli si rimanda alla loro pagina. Se qualcosa qui e' diventato inesatto, scrivetemelo e lo correggo.
Where the free tool starts costing something else
Quotes that become invoices. If you sell fixed-price work, the quote is where the job is won and where the scope is set. Quoting with optional lines the client can accept or decline, then converting the accepted version into an invoice without retyping, is a different daily job from invoicing alone.
Cross-border invoicing. The client's VAT number on the document, the reverse charge wording, the currency with its exchange rate and date. Get one of those wrong and the invoice comes back — not because the client is unhappy, but because their bookkeeping cannot record it.
Time and contracts in the same place. If hours and signed agreements currently live in two other tools, the copying between them is where the errors come from.
What you give up by paying
Bookkeeping. Wave's centre of gravity is accounting — Flowzivo has no double-entry and no bank reconciliation, and if you use Wave for the books rather than only for invoices, that part has no equivalent here.
This is the same boundary as with any accounting platform, and it is worth being blunt about: Flowzivo produces documents and reports, your accountant keeps books.
Pricing, honestly
Flowzivo is 30 days free, then €9 a month or €90 a year with everything in it, and €19 a month if you want overdue invoices chased automatically. That is the whole price list.
The honest framing of nine euros against free: it is worth paying only if it removes a second tool or an error that costs you more than nine euros a month. If it does not, do not pay it.
The case against switching
If Wave is working, switching costs you a working system for a marginal gain. And if the reason you are looking is a single missing feature, check whether a free tool plus a template solves it before moving your whole billing.
The test that settles it: open the demo, produce the invoice you actually have to send today, and time it. If it is not clearly better than what you do now, the answer is no.
Try it with your own numbers
The demo runs the real product with example data. Nothing to install, no account, and anything you type is yours to keep.
No account to look around. Example data, and anything you add is yours to keep.
Questions
Why pay when Wave is free?
Only if it removes something that costs you more than the subscription: a second tool for quotes, a second one for contracts, or the errors that come from copying between them. If it does not, free is the right answer.
Does Flowzivo do accounting like Wave?
No. No double-entry, no bank reconciliation. It produces invoices, quotes, contracts, expenses and reports, and your accountant keeps the books from those.
Is Wave available everywhere?
Availability and included features have varied by country over time. Check their site for your country — that is the sort of fact that goes stale on pages like this one.
Can I move my Wave invoices across?
No import. Clients and open invoices are re-entered; the history stays in Wave and in your export.
Can I try it before paying?
30 days free with no card, and a demo you can open without an account or an email address at all.