Check second hand and resale shops. Also consider renting as the boys do their tuxes. Or sew, if you have that skill. Don't try anything radical.
Many department stores do free make-overs.
Have Mom file and polish. There is no need for a salon manicure. I am a dedicated nail biter, and opted for a pair of lace gloves. Then you know what needs cleaned that day. If you don't finish, you know you'll get another chance next week.