"when in the market can I filter to see the price of an item or a rental price of an item in DEC or Credits?"
Hopefully I can help with this one... try using peakmonsters.com
You can link to your splinterlands account to see your cards, sell them, rent them, etc.. You can also easily buy cards, fliter on a variety of attributes, and see how much DEC or Credits you have.
RE: A New Players Impression on Splinterlands