Why is it cheaper to buy Generic medicine?
Companies manufacturing generic medicine have not invested in development or trial, hence a huge overhead cost is avoided, which gets passed on to the consumer. If you have more than one generic drug manufacturer making same drug, then competition brings down the cost much further, basically market forces dictate the cost.
Is there a difference between Patent and Generic drug? Theoretically, both are same in effect, meaning both drugs should have same efficacy (effect), except the Patent drug is manufactured by only the holder or his subsidiaries. However, they can differ in shape, colour, flavour etc.
Why are generic medicines not popular?
They are not marketed / advertised like a patented drug or branded drug, hence not well known. Though the rules about manufacturing generic drugs are clear, namely, it should be same in efficacy and side effect profile like the original molecule, there is no assurance of the same, as many companies that manufacture these drugs are unknown and hence a shadow of doubt.
Does a drug have different names?
Yes, each drug has at-least two names. Generic name and the brand name under which the company sells.