So there's two options i suggest

If you want to connect two players for cheap you can get the hde ps2 adapter HOWEVER you will have to follow a guide and have a seperate program running to make sure the game recognizes the pads as buttons and not analog sticks which can't go two directions at once.

Your other option is buying two of these which pretty much work straight out of the box and can be used for other stuff if you want to.

I've owned both now, i bought the HDE adapter then bought two mayflash since I made a linux Openitg machine and couldn't get the fix working on it. I do suggest the mayflash adapters just because they pretty much have an automatic dance pad mode which recognized the inputs as buttons instead of analog sticks and you don't have any other programs running

but hell if you want to pay for postage i can just send you the HDE adapter at this point since I don't really need it anymore.

https://www.amazon.com/Dual-Controller-Adapter-Converter-Playstation-2/dp/B001AATQ0Y/ref=sr_1_2?ie=UTF8&qid=1464803841&sr=8-2&keywords=playstation+2+usb+adapter

YMMV, I bought this exact one in 2013 and could not get the dance pad mode to work, so socd (simultaneous opposing cardinal direction) was blocked.. aka you can't do up+down/left+right jumps

this 1

No I didn't. Lol

http://www.amazon.com/Dual-Controller-Adapter-Converter-Playstation-2/dp/B001AATQ0Y/ref=pd_sim_63_1?ie=UTF8&dpID=41o9v3ErvyL&dpSrc=sims&preST=_AC_UL160_SR160%2C160_&refRID=033J3ZB368S4MPR6DBWD

Found this via a quick amazon search:

HDE PS PS2 USB Dual Controller to PC Adapter Converter https://www.amazon.com/dp/B001AATQ0Y/ref=cm_sw_r_cp_api_DQYyxbWYAR2PT

Seems like it should work, but honestly I recommend getting a ps4 controller since it's generally the same thing, but wireless and is mapped to most configs automatically. Make sure you have bluetooth connectivity if you want to use it wirelessly though.