a 1500-invoice package from blinksale (which only does invoicing) costs $49/month. harvest's business plan costs $90/month and is also geared towards projects and invoices only.
Independent contractor version that is much cheaper could be useful, and would be necessary to compete with a spreadsheet.
In the past I have used spreadsheets that I export to pdf and send to the clients that look almost exactly like this format, and manually managed them.
I think simpler is better. A single price makes it easier to decide whether to use the system at all. Of course, it shouldn't be too high, but I don't think $59 is too high.
Simpler is better, but not for pricing.
Look into variable pricing theory and price discrimination, it offers higher potential profits. If you do stick to fixed pricing, make sure you do at least a minimal amount of research to determine the optimal price. YOU don't think 59$ is too high, but whats the optimal price for profitability?
Why is it, then, that services seem to trend towards all-you-can-use at a flat rate? Even when there are lower levels of service (in whatever), they're usually ridiculously less service for a bit less price, which seems to just be a way to drive people to the One True Price that the provider really wants.