The price is not the specification
A price under $600 tells you what the seller hopes to charge on the day you look. It does not tell you the assisted speed, whether a throttle works past 20 mph, or which wattage figure the statute uses. Virginia defines an electric bicycle with a motor input of no more than 750 watts. Maryland uses a motor rating of 750 watts or less. Class 1 and Class 2 stop at 20 mph in both states. Class 3 pedal assistance stops at 28 mph. A peak-watt headline can sit on either side of those rules, and the headline alone does not say which.
This page does not list a best bike under $600. eBikeQuest has not ridden a bike in this price band, and a ranking would be a list of products that happen to exist, not a test. Sale prices also move. Copying today's banner into a guide would make the page wrong the next time the seller changes it. The useful question is what the product page leaves out.
What one manufacturer page actually shows
DTTZH's A12 page is a concrete example, not a recommendation. The specification block lists peak power of 1000W or 2000W, 14-inch wheels, and batteries of 48V 15Ah or 52V 25Ah. It does not list an assisted speed. A warm tip says the 1000W version may ship as the current model or the previous one. The legal disclaimer says the vehicle is a Class 2 electric bicycle limited to 20 mph. The spec block and the disclaimer are both on the page, and they do not answer the same question. eBikeQuest does not confirm the Class 2 label from that page.
The F6 page from the same seller shows why the brand name is not a class. One specification line lists 20–30 mph, 38 mph, and 50 mph, with peak power up to 5000W on the fastest column. The disclaimer is the same Class 2 sentence. A shopper who came for a bike under $600 can land on a family of products that the manufacturer also describes at 50 mph. The DTTZH guide keeps those columns apart and does not publish a model profile for them.
The tradeoffs that show up in this price band
Warranty length is short on the pages checked here. DTTZH covers the frame, motor, battery, and controller for one year from warehouse shipment, other parts for three months, and not the tires. Labor is not described as paid. A one-year parts warranty is a different promise from a shop that will fix the bike. Certification numbers are another gap. The A12 and F6 pages did not name UL 2271 or UL 2849. Absence of those words is not proof of a hazard, and it is not a certification either.
Washington, DC adds a speed problem even when a disclaimer says 20 mph. A motorized bicycle cannot be propelled faster than 20 mph on level ground. A page that also lists 38 mph or 50 mph in the same family is not a District commuter until the bike the buyer receives is actually limited, and the page has to say so in the specification, not only in a disclaimer that the table contradicts. Brakes, weight, and rider height still have to be read on the specific page. This guide does not fill those in from a different model.
What to check before ordering
Ask for four numbers in the seller's own words: assisted speed with the throttle, assisted speed while pedaling, the motor input or motor rating rather than peak, and the brake type. If any of those is missing, the class is not ready to use for a trail or a commute. Write down which version is in the box when one page covers two peak-power figures. Save the serial number if the seller tells you to.
Then read the class guide and the law page for where you ride. A manufacturer link on a brand guide is a way to check the current page. It is not an endorsement, and it is not an Associates link. No Amazon search result is used here, because a generic search is not the bike.