For a cheaper alternative to the Hotsling, try E-I-E-I-O Babygear slings (www.eieiobabygear.com). Mamasource moms also get a 10% discount (use coupon code Mamasource08). I sell these slings and have used them extensively with my two sons. They are almost the same as Hotslings except that they aren't stretchy and don't have any padding (which I've found is not helpful anyway and just adds to the cost). I get the vast majority of my fabric at discounts (often because it is discontinued), so I keep costs down.
Pouchstyle slings like these and Hotslings are the best type in my opinion because (1) they are the easiest and simplest to use, (2) they are the most comfortable for your back, (3) you can use them in a variety of positions with newborns and toddlers, (4) there is nothing to adjust, nothing that will break, nothing that will dig into your shoulder, and no bulk, so they easily fit into a purse or diaper bag. There is only one downside, which is that because they are not adjustable, you do need to buy a separate size for separate users in some cases. Some people also need a smaller size for the sitting position than for the reclining position (i.e., a newborn), although many people don't.
Getting the right size is key to success with a pouchstyle sling, though -- if you can't get the sling to work, definitely consider that you might need a different size.
If you are anywhere near Littleton, MA, I'm also happy to get together for a personalized fitting/use session. We also have a 9-month return policy (as long as you've only tried the sling on and have not used it).
Congratulations on your second baby!