Pretty bland, but serviceable, and it gets some goodwill for (I've heard) being more wholesome than harem. If this is your genre then I'm sure you'll have a good time. For the rest of us, I feel like it's unlikely to provide anything we haven't seen before. 2/5.
Also, I'm really tired of slavery in anime being treated as morally neutral (or only bad if the master is bad). At least this time MC freed the slave he bought, but I hate that he put quite a lot of money into the pocket of a slave trader. Especially since I don't think the story would be very different if she was a homeless kid instead. Like, she could be sitting dead-eyed in an alleyway and he could see her and be like "i can't help everyone" but then feel guilty as he's sitting down to eat dinner and show up back in the alleyway with a plate of food for her and she just follows him home from there.