I wouldn't rely on estimates of value from home sites. If you want an accurate representation of your homes value I would suggest having an agent do a CMA for you to determine your property value in the current market.
I got a USDA loan when i purchased my first home in 2012. You can get 100% financing but there is a fee involved that will be added to the sale price, it was $2500 back when i purchased but this may have changed. The home must be in a certain area and you need use a lender approved for USDA mortgages.