How many calories does this potion have?
Alchemists often make more money than any other profession, as they produce expensive consumables that every class wants more of. You can stick to the basics or shift to more specialized markets, but whatever you do, you'll be making things that lots of people want to buy. Raiders in general and scouts in particular will be your bread and butter. Competent scouts never leave a city without a full compliment of poisons, and most raiders who take their role seriously come equipped with an array of stacking potions to make sure that they maximize their effectiveness against the most challenging monsters in Norrath.
Unlike most other professions, alchemy remains relatively the same as you increase in tiers. You get access to some newer, rarer recipes as you level, but otherwise you're mostly just increasing the rank of your old potions as you continue in your path to mastery. Each potion combine that you make can add up to ten potion doses, and they stack up to 20. Try to get the best results possible out of your crafting so that you get the most product out of each resource combine you make to increase your experience gain and decrease your expenditures. You can also produce essences, which buff the skills of fighter classes. It helps to actually have someone that you know wants those items before you actually craft them, however.
Cure potions are some of the most common sellers, as it gives healers who would otherwise have to cure things more time to focus on other things. The re-use timer on these potions is only 15 seconds, so many advanced dungeoneers and raiders carry full stacks of these potions wherever they go. They come in many varieties for every sort of negative status effect, and at different tiers as well. Essences of Health and Power restore either attribute instantly, and there are also other potions that increase your in combat regeneration for those statistics. Generally, the power potions sell better, as healers often take care of most health problems for people grouping. Rare, high tier potions sell for exceptional amounts, but the ingredients are commensurately expensive. Be confident that you can get a perfect combine on those before you shell out for the rare ingredients.
Alchemy really makes a great support tradeskill for any class, but the benefit of poisons - which are a major benefit of the scout classes - make it especially attractive for that career path. So long as you keep up with your tradeskill leveling, you'll get lots of use out of alchemy so long as you use the potions within your current tier.