損する そんする to lose
得する とくする to make a profit
A friend used the first term, そんする, when she was talking about going to the supermarket to find it closed and having to go back later. So rather than ‘lose’, perhaps ‘lost out’ or ‘wasted time’ would be a better translation?
とくする can be used, for example, when you feel like you’ve got something for a good price; when you pick up a cheap bargain. Maybe in this case it would be similar to かちがある – value for money?