Companies with revenues in the <$10.000.00 per month range usually go for 1x yearly revenues.
Companies with revenues in the $25000.00 per month range usually go for 1.5x yearly revenues.
Companies with revenues in the $1000000.00 per year range usually go for 2x yearly revenues.
Companies with revenues in the $5000000.00 per month range usually go for 3x yearly revenues.
Anything larger is usually a publicly traded company, and is a different situation for buyouts/stock.
Also, if you have a huge growth rate, or your own data center, important proprietary software, patents/trademarks, or a well-known/household company name...that would affect the overall offering alot.
Other things come into play as well...including what exactly you sell/focus on....what additional services you provide, profit margins, etc...Someone will pay more for clients paying $100 per month, then they will for $9.95 accounts. Then again if you meet the right buyer, a large amount of smaller accounts may be more valuable to them, then a handful of really large ones...for they may think they can sell them value-added servers or increase their plan packages/sizes. You may be a perfect match for buyout for one company, but a waste of investment for another. Aother factor to keep in mind is competition....someone may buy out their main competitor not just to gain their client base and revenue, but also to get them out of the game and obtain all future business they would have gotten. In that case oe managed server provider would pay alot more for another managed server provider he competes with every day, than he would for a software development company with the same reveue as his direct competitor. What it all comes down to is who is doing the buying, and what they focus on. This is a general idea of pricing, but you my get offered a price that is an insult to you, or you my get lucky and walk into a sweet enough deal to say it's time to sellout. Never sell out to quickly though...especially if your growth rate is really high....you may be worth twice as much next year. On the other hand, don't wait for the industry to level off, because buyers pay more during the climax of industry growth.
OK, that's it for my work break...back to actual business now