Be careful with your money (investment). If you buy a low end Title bag from Dick's, and the filling material is improperly seated inside the bag, it can ruin your experience with striking.
At the least, if you do buy a bag from Dick's, check to see that the filling material is evenly distributed and that there are no rock hard spots. Make sure the bag is not unusually bottom loaded, ie all the filling is at the bottom, and the lower 3 feet are rock hard while the top 3 are totally empty.
In gear, you generally get what you pay for. For example, cheapskates buy Title or Top Contender gear when repeatedly proven IMF and Ultimate Classic gloves cost only $70. Just an example of a short-term cost saver that isn't worth the long term consequences.
It really depends on your budget. A 130-lb canvas Thai bag costs under $200 before shipping from KO fightgear. Bags by Windy and Fairtex cost around $300, with similar product put out by CSI/Ringside at around $100-200.
If you are in the $100 spending range, picking a bag up from Dick's could save you $30 in shipping, and what you see is what you get. If you shop smart in the store, you could have a serviceable bag for a decent period of time.