Can someone provide me with a good/detailed info on how to shorten the sleeves to my suit jacket?

You are going to need to detach the lining from the sleeve hem, shorten the sleeve, and then retack the lining by hand to the inside of the sleeve.

If you’re not familiar with this type of sewing, you might want to check with a dry cleaner and see how much they charge for this sort of work. Even at $30, it’s a good deal on a $17 suit, because correctly done, it will keep the suit looking professional. It’s not what you pay, but the value. A $500 suit is a $500 suit, even if you pay $17 for it.

Paying a professional tailor for a simple repair is usually very affordable, you might want to look into it. I know around here you can have pants or a skirt hemmed for about $8, so that might be worth checking out.

I agree with the others that unless you’re adept with a sewing machine, you really should pay to have it professionally done. I did a quick search of tailoring rates and it seems that this would cost you around $30, with the price being a little higher if the jacket has buttons at the cuffs. Like @BarnacleBill said, because the suit itself was so inexpensive, paying to have the tailoring done is still a pretty good deal. Think of it as a $50 suit rather than a $17 suit.

You can check out a how-to article here if you want to see if it’s within your own ability.

I got sleeves, AND the bottom of the jacket done for $30 at a tailor, so it shouldn’t cost much to get just the sleeves done! $10—$15 max!