Variable Power Supplies Nice Little Power Supply What Kind Of Variable Power Supply Should I Purchase?

What kind of variable power supply should I purchase? - variable power supplies nice little power supply

I need a power source, a variable voltage of up to about 15-20 V DC can deliver, and) a variable frequency sinusoidal AC signal (with a similar maximum load. Every product or company recommend? Affordability is always a good thing, my budget is very limited.

Thank you!