I work at a nursing home, I work on a tight budget too, we used to play with quarters but people will steal them or miss place them so steer clear from that headache. I use makeup, jewelry, personal hygiene products such as shampoo conditioner lotion mouthwash deodorant, and food. I use candy as well but also cookies, canned goods, ramen noodle bowels, pop is a big one they all want pop, juice but I try to keep all prizes under 25-50 cents. I self bag some items as well, get snack baggies and put only a few candies in each baggie or cheese puffs. I also try to always buy generic or on sale! We play Bingo only 3 days a week for an hour as well and yes without food or prizes it is hard to gain attendance.
You will always have perpetual complainers, literally if they dont get exactly what they want they complain, its ok!
I have just come to accept that some people just do not like to participate in activities. All people do well one on one but we just do not physically have that much time in our lives. To me I just try to always have something new, I inform them of the activities each day and if someone out of the ordinary comes its a win!
To save on outings try to find places that will do things for free or highly discounted, museums have a lot of free activities, local art centers, lots of outdoor concerts and such in the summer. I always call the restaurant we decide to go to in advance to see if they will give any sort of discount. I do pay for my residents meals with my budget though so I understand that gets costly.
I hope this helps!