This drum pad looks pretty good, looked through the reviews and while it's not really professional grade, it seems good for casual usage and practicing. Pre-owned there's currently one available for $135. Alternately if you need something cheaper you can get a roll-up drum pad for $40 though never having used one I can't really say how good they are, so it's worth checking reviews on various websites. If you can it'd be better to put more money into your purchase and get something that will last longer, but I understand since you want to do this in the course of this year you might want to get something cheaper since it will be quicker to save up for.
If you can't find anything suitable online, try local pawn shops or second hand instrument shops. If you go into a store, see what they have in stock and then go back and research it to make sure it isn't awful. There's plenty of crappy instruments for sale lol. Second hand instrument stores often have higher quality products but for a higher price than a pawn shop. Pawn shops aren't always aware of what they're selling so can occasionally sell things for very good prices without even realising what a bargain they've made. Because the staff are (usually) not music specialists it's more likely you will buy something faulty from a pawn shop so make sure the instrument is in a good condition before buying and test out every last thing, as the staff may not have done that themselves.