Could there power source that can provide unlimited power? It has to peaceful like wind or solar but be able to be moved if need. It has to able to be moved by air and by land, water would be helpful to but is not nessesary. Most of all it has to be able to power a small home like a trailer. Any technology level answer can work. I will take answer for tribal, medieval, modern and future times. Could there be a power source with all these qualifications and if so what would it be?
A realistic answer would be something in line with multiple power sources. For instance, you wouldn't only want solar power, especially during Monsoon season, or during winter.
I would suggest a wind power source, a light power source, and possibly a movement (read: watermill) source.
Since I am at work, I am blocked from websites such as ebay and amazon, however, Wind turbines and mini-solar arrays are possible to purchase. A watermill source of power could easily be fabricated from a wind turbine with altered fins.
Pre-modern sources of power would be much less effective than today's standards; although they may be just as acceptable given more extreme circumstances.
Since your question only asks for one source of power, I would suggest a turbine that can swap between water and wind sources depending on the weather.