If you want Dual Variable power supply circuit that covers most applications. This circuit may be what you’re looking for. The price you deny difficult. With the following features.
1. On signal mode can supply DC voltage between 0 volt and 60 volt
2. Can provide DC dual variable on positive, negative and ground are +/- 0-30 volts.
3. Can supply current out maximum about 1.5 A.
4. Use the most popular IC are LM317T and LM337 circuit, so do not have to worry about finding the device, and it certainly easy.