I do home daycare and my kids go to a regular, no lid cup at about 20 mos? I use either the IKEA plastic cups or a set of plastic "Juice size" cups I got at Target. The benefit to the juice size cups (you might find at any discount store), is their size. They are narrow and short so they fit perfectly for those small size hands. If you outfit very young children with the proper size tools they will be more successful at an early age. I remember my Momma using the same juice size cups for us when we were children. As we grew, we graduated to what our hand size could tolerate and work with.
Take and toss cups are a bit too tall and wide, IMO, for early success. Altho at 5 years old, I would think any cup should really do?
IMO-people are WAY too dependant on sippys for kids these days (and diapers and PU's for that matter, but thats a whole other subject peeve of mine). If I can do it , year after year, with as many as 8 children in my care (all generally age 3 and under, without any sort of helper assisting me)...why can't a parent do this?
Sorry...I didn't mean to hi-jack with my rant..but my advice...seek "juice sized" cups. Much easier and proper sized for success for small children.