Within this budget you need to be ruthless about quality and relevance. A cheap gift is immediately obvious so the strategy here is to choose something genuinely useful rather than trying to be impressive. A good mug, a proper set of socks, something for his desk that he will reach for daily works infinitely better than something token that costs more but means less. At this price point avoid anything that screams budget gift. No novelty items that will break in a week or sit unused. Instead choose items that improve his actual life in small but genuine ways. These are gifts that prove you understand what he needs without spending a fortune on it.