As you have asked about the free online college courses with certificates, I am giving you some information about it, check below for the details

There are a number of providers of online courses who put together university course materials in form of videos, texts, lectures and interactive classrooms
These courses are free and open for anyone interested.

I am mentioning some of the courses:

HarvardX

Harvard University in collaboration with edX offers a range of free online courses to students in a variety of subjects. The courses can be taken up by students and upon their completion they receive a verified certificate for a small fee.

Yale Online

The famous Yale University has taken up dedicated online learning initiatives by launching Yale Online.
It constitutes of learning resources made available to students wanting to learn online.
Under the online education, there are both, for credit as well as free online courses.

Alisona

They offer standard-based certified courses in a range of subjects.
These courses are free of charge and they all provide high quality resources to finish the courses.

Open2Study
On this web portal students will get a chance to explore a number of courses ranging in many subjects.

Coursera
This platform provides access to free online courses developed by top notch universities across the globe.

Udacity
Udacity is another famous online platform that offers certificate courses to students for free

Future Learn
They offer a diverse selection of courses developed by leading universities from across the globe. The courses are available online and can be accessed from any place.

NPTEL
National Programme on Technology Enhanced Learning (NPTEL) is an initiative by IIT and IISc wherein online courses and certification is provided to students.

OpenLearn
This platform provides a high number of educational resources for students across the globe. The courses vary in length and the type.

Saylor
This is a non-profit, fully online academy which offers a wide range of courses for students to choose from