Start properly don't even think about making 20 quid a week. Go get discount Udemy courses and take control. Buy a Cpanel hosting learn the ultra basics of setting up a wp environment - or do it on mamp first and learn how to make a free woo commerce store. No money means you need to do it all yourself, you've no choice.
I'm taking the evening off and boozing, hope to catch me a troll or three @MisterF @bartosimpsonio
If you don't know what MAMP is go watch youtube to set it up, go learn your very first conf file updates and php.ini that's one you'll need to understand. Learn file paths, this tiny little function will save you days understanding what file paths controlling your memory limits - phpinfo()
Learn some super simple stuff like some mysql queries for moving a site, you only need 4 for a quick move
UPDATE wp_options SET option_value = replace(option_value, '
http://www.oldsiteurl.com', '
http://www.newsiteurl.com') WHERE option_name = 'home' OR option_name = 'siteurl';
Just pump that query into google, you'll find the other three(with many more basic queries but you won't be doing cdn or similar just yet) - guid, post meta, post content are what you want to look for.
Since your targets are tiny: 12 months of front end css your good for 100-150 quid a week online, even with a sea of poorer countries doing it cheap as chips, you'll find a contact if your english language is good - let's be honest once you can move elements round a page you can build a PBN network similar to other lads who are renting their assets out. Now before you go and do that you need to know all sorts of things which I am not going into, you should ask veterans like
@MisterF he gives away high end info like I am in this single post.
Feel free to disregard the advice but I learn't the hard way and lost a great deal of time, as you will. You'll not get any better advice especially free, not in this forum, I sacrificed this time I could of written a piece for a random pbn in the same time, but I am also troll hunting.
What's better 20 quid a week now or 150 a week in 12 months time, or 500 a week in 3 years?
Patience lad, build foundations - and all this talk of stores, you don't even need a store with 150 quid budget. You need to get writing and make a nice piece of web property and get some social going on it and drive a bit of relevant traffic worry about making cash when you've people wanting to buy on your website meanwhile your using your Udemy courses and implementing all you learn on it.
Decide are you an seo, web dev, dev ops, social media guru, or ? Then get learning - I'll say this for dev/ops first. You will blow the competition away with structured data, load speed, tech implementation such as amp - I piss myself with laughter looking at seo guru structured data, load speed, amp plugin pairing. You'll build sub half second websites and you will not really want to frequent forums like this for fear of running into noddies like
@bartosimpsonio &
@MisterF that think a couple of mid-level questions represent Above Top Secret info.