Property Management Tool Recommendation

[Charles Phanumphai]

Hi BP community - 

We have about 20 properties and growing, that we manage on MS Excel.  Properties are a mixture of short and long term rentals.  What software tools would you recommend that would help not only manage the properties but also with invoices and year end taxes, etc.

Extra bonus question - to our limited knowledge the rule of thumb for purchasing a company is to pay 2-3 time the company's income.  Is this true for property management company purchase as well?  Where we would purchase their existing company, clients, and books.

Thank you!!