Since baseboard heaters come in many different wattages vs. lengths I guess the best answer would be, you can load up to 2880 watts of baseboard heaters on a 15 amp two pole breaker at 240 volts.
The function of a breaker in your home is to ensure that too much current doesn't flow in a circuit. An over-current condition could cause a fire or be a shock hazard. Therefore, you answered your own question and the answer is 15 amps.
A 20 amp circuit with #12 gauge wire will work in any event but if the nameplate recommends a 15 amp circuit then #14 gauge wire on a 15 amp circuit is sufficient. In either case you will have a double pole breaker and your equipment may not require a neutral. Always run a grounding conductor.
It costs about $22 a year, or about $2 a month. It really depends on how much you run it.
It depends how much you pay for electricity. A 15 Watt bulb would consume around 134 kWh of electricity. In the UK, electricity is around 10p a kWh, so it would cost £13.40 to run the bulb.
Electricity
First, determine the current necessary to operate the appliance. Read the installation manual to find out the manufacturers recommendations. If the existing outlet does not supply sufficient current to operate the appliance, you'll need to run a new wire and install a larger breaker in your main breaker panel.
is it polesible to run a range of appliances on a single 15amp receptical
A 4 x 4 electronic display should run on standard a 110v 15amp plug. The displays don't draw that much power as most them run on LEDs. It can vary by model. What you can do is but a meter. you plug the machine into the meter and it will tell yu how much energy the machine uses.
A 20 amp circuit with #12 gauge wire will work in any event but if the nameplate recommends a 15 amp circuit then #14 gauge wire on a 15 amp circuit is sufficient. In either case you will have a double pole breaker and your equipment may not require a neutral. Always run a grounding conductor.
It costs about $22 a year, or about $2 a month. It really depends on how much you run it.
It would not take very much electricity to run a small pond fountain. If it is run 24 hours a day, it would probably cost less than 3 dollars per month.
It can run on one or two 1.5v AA batteries ...
Hybrids run either on electricity or on fuel.
Most tanning beds run about 100watts
You can always run under a receptacles rating. This just means how much current can be drawn thru the breaker before it will trip.
It may be one of the coils that needs to run with a resistor. Check the normal application of that coil. If you need to pick up a resistor to make it run right, it would be a relatively inexpensive repair.
Microphones run on electricity.
It depends how much you pay for electricity. A 15 Watt bulb would consume around 134 kWh of electricity. In the UK, electricity is around 10p a kWh, so it would cost £13.40 to run the bulb.