MIx, since your prices are pretty low for events, your clients should not have a issue with paying 40% to 50% up front as a deposit. Very lowest I would go with in your price range is 25%.
I was 50% FOR YEARS up until the last 5 years or so. Back when my booking were almost all below $1,000 I had no problem getting 50% , and I never felt that asking that much was hindering my sales in any way. ...I started to feel that I was asking too much of a deposit amount when I was quoting above $1,000 regularly. Booking a $500 birthday party and getting $250 as a deposit was quite easy. Booking a $850 wedding, and getting $425 deposit was very typical.
I went to 33% for a while, and now I am down to a set amount of $200 to $350 depending on if it's a party, or a wedding, and if it's a budget package, or higher price package.
I don't know if it was the higher price point, or that my clients expectations were changing (or both), but I got the feeling from clients that asking 50% up front was 'asking for too much" in order to book around 2014. So I went down to 33%, and that seemed to work for a while. And now I just do set amounts.
I feel at $350, if the wedding cancels, $350 is enough to walk away with for doing very little work up until that point. ...Smaller parties are usually booking less than 75 days in advance, so the lower deposit feels justified in those situations, and it's very rare that a birthday party cancels once they have paid a deposit on it any way. I don't think I have ever had a birthday or anniversary party cancel before. I have had weddings cancel though.