Different stages need different tools
The cheapest accounting setup for a startup depends primarily on stage. A pre-seed founder running on a laptop with two contractors and no employees has different needs than a seed-stage company with five hires and a closed institutional round, and a Series A company has different needs again. The right answer is to pick the tool that fits your current stage plus 12 to 18 months of growth, not to over-buy at pre-seed for what you might need at Series B.
The migration cost between accounting tools is real but manageable. Most tools export to CSV, the major destinations import it, and the migration can be done at year end with a clean cutover. The expensive migration is from a tool that does not produce investor-grade reports to one that does, mid due diligence, when you do not have time to do it cleanly.
By stage
Pre-seed. Founder on laptop, no employees, maybe a contractor or two. Wave is free and competent. The accounting complexity is low and the cost should match. The trigger to upgrade is the first W2 hire or the first institutional round.
Seed. First hires, typically two to ten employees, payroll matters, and investors expect clean books. QuickBooks Online or Xero with Gusto for payroll is the default stack. This is the stage where investing in accounting infrastructure pays back, because the next round's due diligence will scrutinise it. Cheap-and-clunky here is expensive-and-painful at Series A.
Series A. Investor reporting becomes formal. Monthly close discipline matters. Some startups stay on QuickBooks or Xero with a part-time bookkeeper or finance hire. Others move to outsourced bookkeeping platforms (Pilot, Bench, Kruze, Zeni) where the platform provides both the software (under the hood, usually QuickBooks or Xero) and the human bookkeeping work. The cost is materially higher but the founder time saved and the investor-ready reporting are usually worth it.
Series B and beyond. The candidate set expands. Some companies graduate to NetSuite or Sage Intacct for ERP-grade financial reporting, especially if they have multi-entity structures or international operations. Others stay on QuickBooks Advanced or Xero with a CFO and accounting team. The decision is increasingly about CFO preference and operational complexity rather than cost.