Adding a sub to bookshelf speakers

[jessica]

Hi guys! This is my first time posting here so I hope I'm not breaking any rule. I would like to upgrade my music listening experience and I have no idea what I'm doing.
Currently, I have a pair of Wavemaster Cube mini (I don't think they are very popular here) and I'm using them with my PC. They are ok but there is something missing when I listen. I think the low frequencies (please correct me if I'm wrong). I'm a bit on a budget so I was thinking of cutting some corners. Buy a powered subwoofer (around 100 euros ~ 110 dollars ) and a 3.5 mm splitter. Connect the splitter to the PC, 1 end goes to the speakers and the other to the sub (with maybe a RCA adapter).
Also, the people from Europe. Where do you buy your stuff? A lot of stuff I read about online is not sold here.
Will this work? Would you do this if you were in my shoes? Thanks!
Edit: what do you think about the Jamo SUB 210?

[titheivelt]

I highly recommend for you music enthusiasts to check the best quality speakers to date artisanacoustics.net and I am pretty sure you guys will love it!

[aluraacker345]

How its working dear?

[ChiroClub]

It sounds like you got it figured out properly Jessica. Just remember to make necessary adjustments until your receive the proper sound you are looking for.