Yeah Amazon is good for some things but Ebay is usually a bit cheaper - esp since the chinese manufacturers use their e-packet service to get really cheap shipping on the small things. (ie. the fan for $1 can't be shipped across town for that price but can come from China and leave them a profit still ! )

$25 is a bit of a challenge but might be doable for a NES cartridge build if you can find a pi zero for the $5 SRP (ie. do you live near a microcenter location)

EDIT :
NEs cart - $3.00 ( http://www.ebay.com/itm/Gray-NES-Case-Cartridge-Shell-with-3-screws-For-Nintendo-Entertainment-System-/302312570966?hash=item46633bc056:g:nBYAAOSw42JZE8Am )

PSU - $3.00 (listed above )

2 SNES USB controllers $6.00 ( Listed above)

Micro USB to USB hub - $2.09 ( https://www.amazon.com/gp/product/B00FGKXY9S/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 ) - has 2 USB and Micro USB power input for Pi zero

Mini HDMI to HDMI adapter - $1.71 ( http://www.ebay.com/itm/Fancy-Mini-HDMI-Male-to-HDMI-Female-Converter-Adapter-Cable-Cord-1080P-/272645772943?hash=item3f7af4568f )

About $16 -- tHen just need the pi zero and a cartridge label ( if you have a printer need a sheet of sticker paper) and a 8 or 16 GB. micro sd card ( depending on what is left in the budget and which is cheaper when you go to buy it ) - So could probably do it for about the $25 !