Hi,
In general, hyaluronic acid (HA) fillers that are more fluid (i.e. less viscous), softer and less likely to cause swelling (edema) after injection are the best filler for treating the tear trough. Each of the major HA brands will have such category of fillers to fill up areas that are particularly contour-sensitive. Commonly used brands include Restylane, Belotero and Juvederm.
Costs will vary due to the product used, seniority, skills and experience of the doctor whom you have chosen to treat this challenging aesthetic area of concern. Typically, such procedures would range between $500 to $800.
Hope this helps!
