yes, i'd say i have an addiction as well. however, here are somethings that help me keep in line and prevent overspending--
1) space: space in my house is very limited, not to mention no backyard. this for the most part eliminates all possibilities of keeping temperates. (not that keeping them isn't possible, but it's more of a pain)
2) uniqueness: because i have limited space, and a decent amount of income, i concentrate on plants that i find to be unique in physiology or in rarity. quality is better than quantity. finding rare plants may take a little work, but it's not impossible. take a good look at my growlist, and you'll find that i have quite a few nice specimens---all this i have amassed within less than a year so yes, it is possible.
3) temperature: my climate does not allow me to keep that many plants that require lowlander conditions to grow. i do have a lowlander tank, but it is only a 2.5 gallon tank-->go back to reason 1.
because of these perimeters i've setup for myself, i am almost complete with my collection, and i can tell you that i am quite satisfied with what i've gathered for myself. there's no need to spend money on the more mundane or common plants---however, like i said, invest in plants that you find the most appealing and dont settle for less.
i've been on the otherside where i kept buying more plants than i could keep when i was younger. as a result of my lack of self control---i lost a good amount of CPs, as well as the money spent on them.