Even though I'm posting the link to the JP wiki here, I'm too lazy to read the article with my current Japanese, so I'm not sure if it covers everything. As for the English wiki, I know for sure that it doesn't have that information by the time I'm writing this post. Without it, translating this following sentence is just impossible:
ギャラがおかしって…ラジオ体操の景品じゃないんだから…The necessary information is as follow:
ギャラ means "pay" and it is basically the only word for it used in show business. ラジオ体操 means what any dictinary would tell you it means. If a kid participates in it for enough days during the summer recess, the community will give him a little present on the last day, which is usually August 31. In my town, the present was usually a notebook or pencils, but from this manga, it looks as though that the present can be candies or snacks in some communities.
"They pay you with candies --- just like the present you get for attending ラジオ体操 !"