I have heard many people talk about aspen pine for bedding. Is there a big difference between aspen and just pine shavings? If so what is the difference. I ask only because I am currently using Carefresh and have no problems other than the fact that it is very expensive. It costs me about $16-20 per month. At the Tractor Supply Co. near me, they sell large bags of pine shavings for about $5/bag. This at least seems more economical being that the bag would be able to last me well over a month. I know that many people say that pine is not the best being that it can cause health problems, but any input would be great!