Can't specify any financial details (sorry!), but the whole process lasted about 3 months.
Legal fees were reasonable using a local attorney that another startup introduced us to (with experience in M&A).
Due diligence included reviewing ROI reports (how well the product works for clients), financial reports of the company (where does revenue stand, how fast is it growing), current customer lists, past customer lists, all support conversations (how happy are customers, how fast are support requests handled), and gathering listings of accounts in-use that would need to be transferred.
We decided on a purchase price before entering due diligence, but saved equity offerings until after the deal had closed. At that point, we brought in our investors, and offered Andrew a priced option to invest (at a higher valuation than the purchase price based on the expanded team and advisors).
If you don't have guidance from someone with experience, you should probably use a broker. And if you don't know the seller super-well, you should probably use an escrow company for the transfer of assets. In our case, we knew we were working with a stand-up guy based on our friendship with Andrew, and how wonderful he was throughout the entire process.
Let me know if I can answer anything else! Matt