Learning a new skill can be an expensive undertaking, especially if you are seeking employment or the company you work for is not footing the bill.
But there are a plethora of free online courses that you can subscribe to offered by reputable organisations that you can tackle at your own pace.
Traditionally, lessons have been conducted in lecture halls on a face-to-face basis - but the introduction of Massive Open Online Courses (MOOCs) and technology at your fingertips, it is more likely to be done through apps like Skype.
MOOCs, shot to popularity in 2011 when Sebastian Thurn from Stanford University launched a series of open online courses, thanks largely to the convenience factor.
Now everyone can upgrade their skills from the comfort of their armchair - or bed - at any time of the day.
The types of skills that you can learn online to advance your career is wide ranging.
You could study anything from computer science, to communications and journalism.
Many of these courses are offered by reputable universities like the University of London, Harvard and University of Strathclyde (see below for 10 free online courses that could advance your career).
Other online learning platforms offer courses that have been filmed and designed by professionals that have years of experience in the specific field that you're studying in. These include the likes of Udemy, Coursera and Skillshare.
But it's vital to do your research and learn about the lecturers' background before you sign up as they vary in skill and experience.
Many of the free versions do, however, try and incentivise students to upgrade to a version that will offer them a certificate on completion of the course or some also offer access to more courses and other perks.
Fees for the certificates vary, but a quick search online by This is Money found some asking for as little as £37.
Some do offer the certificate as part of the course, but others don't, a point worth considering if your employer needs evidence of your new skill.
If you're willing to part with more money there are some courses that will cost you couple of hundred quid upon sign up.
For example edX, created from a joint venture between Massachusetts Institute of Technology (MIT) and Harvard University, offers two types of programmes for learners to take for career advancement, including MicroMasters and Professional certificate programs.
A spokesperson for edX says: 'The average cost of a Micromasters program is $1,000 (£761.51), and the average professional certificate program costs $300 (£229).
'At edX, we offer our learners the choice between an audit (free) and verified (paid) track.'
For those that have completed a professional certificate, edX has found that 93 per cent reported positive career outcomes which included an increase in salary, promotion or giving the learner the ability to change careers.
When it came to the Micromasters edX said 91 per cent of learners had reported positive outcomes for their careers, including raises and promotions.
Similarly, Coursera says in its learner outcomes survey in the Harvard Business Reivew published in 2015 that 84 per cent of career-focused learners who completed courses reported career benefits.
Coursera adds that other personal benefits were also noted with 72 per cent of learners completing the course reporting confidence gains.
Nearly 50 per cent reported benefits from connecting with peers from around the world.
It said: 'The verified track includes feature-based value adds of graded assessments and unlimited access to the course, as well as certificate of completion upon successfully passing the course. '
The spokesperson explained that fees are charged for some courses in order to be able to offer free versions to those who want them.
'We charge a fee for the verified track, which allows us to work with our partners to fund the running of the course, grade learners' work at the highest level.
'However, we recognize that not every learners' goal is to earn a certificate, which is part of the reason why we have a robust audit (free) experience.'
The free experience also supports our mission of providing affordable access to high-quality content for all learners.
A downside to signing up to MOOCs is that the completion rates for these types of courses are pretty low.
Industry commentators put these rates at around eight per cent and put it down to the fact that many struggle to keep motivated in a self-paced learning environment where there's little supervision.
If you plan on joining a free course it's probably best to ensure that you're familiar with the course outline and that you're sufficiently motivated to complete it, particularly if you're enticed by some of the paid premium versions.