How much does this cost to the nearest dollar?

Starboosa Telescope Tube Kit for Cameras and eyepieces - Length 3mm 5mm 7mm 15mm 20mm 30mm - on Both Sides
The extension tube kit is used to obtain the correct image focal length or exact spacing required, thereby solving the spacing problem in astrophotography. The required spacing can be achieved by combining several Tube of different length;you can use 1 pieces ;4 piece of the extension tubes as you like. The threads on both ends make it versatile. External thread M42 * 0.75; internal thread M42 * 0.75; a series of focusing problems are eliminated. By combining multiple extenders of different lengths, you get the right focal length to focus with the camera or eyepiece.

Price is $28.00
Price: $27.59