If you are going to try playdough, it's much more cost effective (and healthier IMO when they eat it) to make your own and it's fairly simple too. I have a recipe at work I can post up on tuesday for those who are interested. Or there is probably heaps on google.
Littlies love playing with real things too so maybe check an op shop for some cheap kitchen items that she can go to town on. Things like scarves for dancing and some simple musical instruments are good too. Getting out in the garden is awesome even at her young age. Get her to help you weed (providing the entire patch is full of weeds and you dont care what she pulls up) or dig a bed in preparation for herbs and vegies. Helping to fill pots is great fun too.
If you are making playdough or doing any baking, get her to help you pour in the pre-measured ingredients. Also, shaving cream and paint mixed together makes an awesome messy play on a table (with supervision obviously). Mixing cornflour and water together makes the most awesome sensory substance but its better for outside as it makes a huge mess. If she balks at things that she has only experienced once dont worry, if you offer it a few times and play with it yourself she may get used to it and find it fun.
Ohh, and spray bottles filled with water are fantastic in the summer time for when she is a little older.