How to monetize free saas?

i have built a easy to use visual a/b testing tool for websites and i am planning to offer it for free since i dont have the resources to market it. So my question is even if i offer it for free is it possible to make some money from this service.? I would be happy if i just got my server expense back. I am considering putting ads or maybe a paypal donate button. Is there any other way to monetize my service? If so plz let me know.

Any monetization scheme (donations, ads, selling subscriptions) brings revenue proportional to the number of users/visitors.

Given the same amount of visitors, selling things works much better than ads which works much better than donations.

So regardless of how much effort you want to put into marketing (i.e. acquiring more visitors), selling is still your best chance to make money.

On a side note "I don't have resources to market" seems more like a self-fulfilling prophecy than an actual constraint.

There are many marketing activities that only cost time, not the million of dollars needed to buy Superbowl ad. In general, so-called in-bound marketing i.e. writing educational content related to your service has the biggest payoff, but there's also tweeting, writing blog posts, writing a good website, writing good tutorials, making video tutorials, participating in communities relating to your product etc.

Google AdSense is a very cheap way for paid advertising (you can test it with very small amounts of money and increase the ad spend if you get positive ROI).

I agree with the other comments that if you have something good it will sell itself but you either need to market the site to get traffic or rely on viral effects. You could add some artifical virality such as charging for the app but making it free (or significant reduction) with a tweet or referral etc

I think you are selling yourself short if you only get your server costs back and I think you could make some descent money if this tool has some advantage over its competitors.

For interests sake I would love to see your data and see if I can help.

A good A/B testing tool is very valuable - if can significantly increase the profit of the company using it.

If someone came to you and said "during the 30 days free trial this product increased conversions by 5%, that will make you an extra $5000 per year, would you like to subscribe to our $100/month plan?" what would you say? (hint: if your answer isn't "take my money now please" you are not fit to run a business).

If your product is any good it will practically sell itself - and in a price point that let you cover the operational expenses with just one or two customers.

Also, no marketing means no people getting to the site - and that means no ad shown and no donations - you have to do the work of getting people to the site anyway.