It’s $200 per year for the indie version. And if you think Blender is hard I doubt you’ll like Houdini.
For Blender you should use left click to select and bind the keys for the normal modeling tools so they’re close together. Stuff like grab/scale/rotate, extrude, make face, box select, loop cut and slide, edge slide, vertex/face selection, smooth should be close together, I have them on the left part of the keyboard. You’ve also got stuff like loop select on alt+select click I think and axis constraints on x/y/z when grabbing vertices and so on. I guess it’s not easy, but it’s fast and efficient once you learn the keys.
For the towers I would use bones, that way you can have a whole tower object with a rig instead of a bunch of separate tower parts which can easily turn into a mess.