We can now pay less for some services and products we want. Venture capitalists are betting millions that we will love this approach.

It’s a fresh take on group buying. Several online start-ups negotiate for their members deep discounts for products/services – provided that enough would-be buyers sign up within a limited time frame.

They offer daily online deals that you can get delivered via Twitter or to your email in-box.

Today, for example, those of us in the San Francisco area can buy sailing lessons for $185 rather than $375 because the deal “tipped” when 50 bought and 52 now have. Or your family can visit the Oakland Zoo for $40 rather than $85 – if enough people say they want this offer.  

A side benefit of such sites is seeing what people in your area think it worth buying or not – even at a discount.

These start-ups encourage members to urge friends (via Facebook and mobile phone app) to also sign up to buy so that they can capture the opportunity to get what they want for that low, low price. 

To sweeten the deal for these encouragers, buyers can get freebies if enough of their friends buy too. (You can also buy something for a friend.)

Two such startups, LivingSocial and Groupon have each raised a whopping $30 million. Both are user-friendly. Groupon is bigger, starting first.  Just last month it attracted two million U.S. visitors.

There are several others.

Which one will break away from the pack and become our “go-to” service of this kind? I’ve enjoyed the savings and the ease of buying two deals at Groupon but LivingSocial will give them a good run for their money (and they both have buckets of it).  Tell me what you think.