Illustrate the effects of each of the following promotional campaigns on Helen's budget line. In all of your diagrams assume the goods are infinitely divisible as are the promotions (e.g. for ii if she buys 1.5 bars of soap then she will get 1.5 bars free). i. a sale on shampoo lowers the price of shampoo to $3 ii. buy one bar of soap get one bar free iii. buy one bottle of shampoo get one bar of soap free iv. get one free bottle of shampoo