Managers self hosted server is priced very competitively even if just used as a single user single business.
Note server renewal is heavily discounted (at least 50% the exact amount has varied). See
https://www.manager.io/server/
Starting a business is alway hard, there are significant start up costs (including purchasing an accounting system). If this is beyond your current means and your business is really that small, then surely just doing your accounting on one computer would be adequate until your business grows.
Moving the data file moved to a shared location or using remote desktop access are also alternatives until your business gets going.