it will depend what your LO likes the most, e.g. music, physical play, art/crafts, and how much you want to spend
our local libraries do "rhyme time" sessions which L loved as a baby (and still does!) - these are free
there are also paid musical/song groups which you can go to
tumble tots/gymboree is a good idea
or a swimming class?
do you have a 'creation station' near you? they do arts and crafts activities for all ages, including babies and are lots of fun.
another idea is to join/go to a play group which might have a mixture of all of the above (except swimming!), plus more general play and socialisation (as your LO gets older)