"I have just bartered some very expensive dental treatment for a website down here in Peru."

Perfect.

Deals like this are great and especially useful in a tight-funds economy.

It won't always fall in place... I've had offers for free personal physical training in trade for marketing consulting. I wasn't interested. So not everything will be a fit.

But the point is to at least remember that cash is not the only way to go about it...

And even in your case, suppose you needed that website but the web guy didn't need the dental treatment... however the web guy needed legal service. And it just so happens that a good lawyer contact of yours DOES need the dental treatment. You offer the dental work to the lawyer, in trade the lawyer is asked to offer his services for the web guy, the web guy is then taking care of your site.

Creative 3-way "JVs" like this are common. Jay Abraham has talked about this as well, so has Dan Kennedy.

When it's just one off deals like this, it can be called a services barter, but on a larger scale, powerful JVs can be setup like this.