$800. Yipes! A 100w panel is less than $200 and a controller for it is about $20.. Some wire maybe $50 if you go crazy.
Yes, you can have more of a portable set up and not have to mount any on the roof at great expense. There are limits as to what each size of controller can handle so you might need two at $20each or just one bigger one at $40.
Note you can buy a 30 amp PWM controller such as the Solar30 for $35 free shipping if you will wait three weeks snail mail from Hong Kong.
It "depends". The main thing is that a regular solar dealer will want about or less than $2/watt for a "12v" panel, while Can Tire and similar places are asking $5/watt. Don't be a sucker!!!
(Also DW reminds me from time to time as required, that being a woman is not necessarily a sign of helplessness, unless she is "playing that card" ! :) )