There are lots of options and places to start. It depends on what direction you want to go. If you want a more reconstruction group based on Indo-European history you can check out A Druid Fellowship (ADF). It's $30 a year for membership and they have a year long dedication course to complete.
For a direction more on practicality and not exactly historically accurate practice, yet based on the Druid revival movement from the 1800s, the Order of Bards Ovates and Druids (OBOD) is a good option, but they are pretty expensive for those outside of the UK. They don't have a yearly due, but the initial Bardic introduction beginner course is a couple hundred dollars due to the amount study material they send you.
For a mixed approach also influenced by Golden Dawn and ceremonial magic, there is the Ancient Order of Druids in America (AODA). They also have a join fee but you can also just buy the books used for the dedication course online or at book stores. Druid Magick Handbook and The Druidry Handbook by John Michael Greer (current Archdruid for AODA) are great for an good introduction to druidry.
I am personally a member of OBOD and ADF, but I also have the required reading for AODA so I have experience with each of those three which typically are the most common druid organizations. The is also a Grove formerly known as Black Mountain Druid Order that recently had a name, website, and focus change that has a free year long Dedicant course on their new site somewhere. There are lots of smaller unaffiliated and affiliated Groves to choose from as well if you have one local to you. There are a lot of good books on druidry out there, and also some awful ones (DJ Conway for example). Keep in mind in druidry we also take pride in scholarly development in our lives and research history and folklore along with magic and ritual. If you have any question I'd be happy to answer or point you in the right direction for the answer. Hope this helps.