I’ll start with the Lindt if only because it is mass marketed and available worldwide. Indeed, it is harder to pick up in the US than it is in China or Italy, where I have found it supplied even in the 7-11 stores.
The 99% bar has 1 g of sugar in the 50 g bar. And, with the intensity of the taste, a little goes a long way.
If you are interested, do not start with these high percentages. But if my experience says anything, it takes a while to wean off the taste of sugar, but it opens a new world.
The most accessible 99% bar is by Lindt, which is mass-produced and can be found at many high end stores. The 50g bar is usually about $2.50-3.50 in the stores, and you can always pick it up at a Lindt store (there is one on the waterfront mall in New Orleans) or online at https://www.lindtusa.com.
As you move away from the Lindt bar, be prepared to pay more for your cacao. These 50-75 g bars are typically $9-11 each. Before I get to those, another reminder that you can buy in bulk for cooking with these 100% chocolates. I make some great layered “nut butter cups” with a topcoat of dark chocolate. The Santa Barbara brand is quite good (https://www.santabarbarachocolate.com), and when you can find it in the speciality markets, the big broken bars from the Belgian maker, Callebaut, is excellent (https://www.callebaut.com/en-US).
One of the two best recommendations I have for a boutique 100% that is astoundingly good is by this San Francisco maker. They have a big line of high % chocolates, but the 100% bar is really special.
The other brand I really like, although it is often harder to find, is the Swedish maker Åkessons. They’ve also got the option of their 100% bar with nibs.
Original Beans (https://originalbeans.com)
French Broad (https://www.frenchbroadchocolates.com)
Pump Street Bakery (http://www.pumpstreetbakery.com/chocolate)
Cacao Sampaka (http://www.cacaosampaka.com/en/home)
Although a slightly different taste, the TCHO company, out of Berkeley CA, makes a melt-in-your-mouth 99% that I like. An 8 oz bag (225g) of little nibbling pieces is about $10.00.