Short answer: solo consultants should keep one general assistant for drafts, one notes or CRM-adjacent tool for follow-up, and a real invoicing system. Do not add an AI billing product until invoices are late every month.
The job
Weekly admin: write invoices, chase unpaid work, log expenses, and turn call notes into next actions. AI helps the writing. It does not replace your books.
Free-first stack
- Drafting: ChatGPT or Claude free tier for invoice language, reminder emails, and scope notes.
- Notes: Notion AI only if your notes already live in Notion. Otherwise keep a plain notes app.
- Follow-up automation: test Make or Zapier AI on one real unpaid-invoice reminder before paying.
See the workflow page: consultant invoicing admin.
What to test in one week
- Write two real invoices with the same brief in your primary assistant.
- Send one reminder email you would actually send.
- Count minutes saved vs minutes spent editing.
- Do not connect bank or client financial data to a consumer AI plan.
Use the scorecard and cost calculator. If you already pay for overlapping admin tools, the stack audit checklist and Premium audit template help you cut before renewal. 7-day trial; code LAUNCH50 for 50% off the first paid month (new users).