Can I sell models created with MakeHuman?

Yes.

From the license section that applies to the exported models:

You can copy, modify, distribute and perform the work, even for commercial purposes, all without asking permission.

The exported models end up being licensed CC0 (Creative Commons Zero). This is basically the most liberal license in the world, and for all practical purposes it places no restrictions on the licensee.

The full license text is available at https://github.com/makehumancommunity/makehuman/blob/master/LICENSE.md

Other formulations of the same question

As it has proven somewhat difficult for new users to understand that CC0 means you can do whatever you want with the export, here are some other formulations of the same question:

Can I use exported models in a closed-source game?

Yes

Can I use exported models in video productions?

Yes

Can I modify exported models?

Yes

Can I re-use and/or sell parts of the export, such as textures?

Yes

Do I have to say where I got the exported model from?

No (but also read [[FAQ:What do I need to do when I use a CC-BY asset?]])

Do I have to pay anything to use the exported model in a commercial setting?

No

Do I need a separate commercial license in order to use exported models in a commercial setting?

No