If you are in the US want to buy your first steel sword either sharp or blunt, my suggestion is to take a look at HEMA Supplies, a US-based importer and reseller of Peter Regenyei's swords that seem to offer reasonable prices. They mostly sell blunt steel feders from Peter Regenyei but they will take orders for custom sharp longswords.
Regenyei is one of the most trusted swordsmiths in HEMA. I personally own a (blunt) Regenyei longsword (a "hand and a half" sword) and I've briefly handled sharpened custom jobs from him, all really good quality.
HEMA Supplies - https://www.facebook.com/HEMASupplies/timeline
One thing to bear in mind, I'm living in Europe so I'm not familiar with the exact shipping costs to the US but I'll be conservative and assume it's rather high, however you might just get away with a sharp sword in the $400 range if you're lucky. If you have to choose between spending a little more for a high quality robust training sword or buying a cheaper sword of lower quality, I would recommend paying a little more.
One last thing that doesn't directly answer your question but I think is important nonetheless, if you are a novice I would recommend getting a blunt training feder. It's much safer to train with if you are just starting out, most clubs will use feders for sparring, and they are cheaper and easier to maintain.
P.S. I prefer to describe myself as a historical fencer rather than a HEMA practitioner.