Yes, both Slack and GetMyInvoices.com offer a Free Trial.
Slack is designed for Freelancers, Large Enterprises, Medium Business and Small Business.
GetMyInvoices.com is designed for Large Enterprises, Medium Business and Small Business.
The starting price of Slack begins at $2.67/Month, while pricing details for GetMyInvoices.com are unavailable.
Some top alternatives to Slack includes Microsoft Teams, Glip, Google Chat, ChatWork, Dialog, Office Chat, imBee, Takle, SPACE Channel and Teamwork Chat.
Some top alternatives to GetMyInvoices.com includes Invoice Ninja, Invoiced, InvoiceBerry, Invoicera, Moon Invoice, Simple Invoices, Billin, CloudBooks, Billogram and Innovo Invoice.