Keep in mind that Ham Radio Outlet has a VERY SHORT 10-day return window and they charge a 15% restocking fee to return non-defective merchandise during that 10-day window. The following is verbatim from their website: "Defective items may be returned for an exchange, return or upgrade within 10 days of the purchase date. Non-defective items returned within 10 days for credit or refund will be subject to a minimum 15% re-stocking fee. Special order items, cut cables, software and books are non-returnable. All return freight charges are the responsibility of the customer."
For comparison purposes, Bearcat Warehouse has a 30-day return window.
Another factor to consider (which applies to the OP as he is located in Georgia per his post) is that Ham Radio Outlet charges sales tax if you are shipping to any of the following 41 states: AL, AR, AZ, CA, CO, CT, FL, GA, HI, ID IL, IN, IA, KS, KY, LA, MA, ME, MD, MI, MN, NE, NM, NV, NJ, NC, NY, OH, OK, PA, RI, SC, TN, TX, UT, VT, VA, WA, WI, WV, & WY. Calculating the 4% Georgia state sales tax on $650 for the SDS100, HRO would add an additional $26 to the OP's invoice.
Bearcat Warehouse charges sales tax only to shipments going to Maryland (where they are located) so the OP would be exempt from paying any state sales tax to Bearcat Warehouse. The $26 saved on Georgia sales tax would more than cover the "almost $20" for shipping charges that the OP mentioned in his post. FWIW