Didn't pass some courses, I can't get my diploma on time, but I found a website that provide fake diploma just same as the real. I wonder if it worth to buy it.

No, it is easier just to print you own if you want to be a fake and lie.

They have no value at all.

Who are you trying to impress with the diploma? If it's for a job, they'll ask you for your transcripts, not a copy of your diploma. Finish your courses and get a tutor if you need one. Then, you'll earn a real diploma.

If you just want a fake diploma to hang on your wall so you can pretend to have a diploma, then go for it. If you want to use it to get into college, or get a job, it's useless. Colleges expect your transcripts, and you can't fake those. Same with employers.

Much cheaper to just print one on the computer if all you want is a decoration for your wall.

Didn't pass some courses, I can't get my diploma on time, but I found a website that provide fake diploma just same as the real. I wonder if it worth to buy it.
No value at all. Employers are aware of this stunt unqualified people pull and they check on them which is EASY to do, meaning you will never get the interview... and if you do manage to and they find out at any point in the future, they can and most times will fire you. As it should be.

That fake diploma may fool McDonald's but won't get you in college, trade schools, or anywhere else you need to go in life for a decent living.