To answer the question you asked (as opposed to questions you may ask later), is there a way to get a monthly payment on a loan that is less than the $150 or so you're thinking it would be thru Disney financing at 10.75%?
The answer is "it depends." It depends on your own financial circumstances. But the general answer is yes.
I get offers all the time from banks and credit card companies offering me personal loans at rates far lower than 10.75%. These loans are for "whatever I please". Some are home equity lines of credit; others are simple personal loans. There are also credit card loan offers that arrive by the truckload--lately, fewer and fewer are for the 0% interest for a year loans (which I used to buy my various
DVC add-on's--always paying them off prior to the expiration of the 0% loan time frame)...but most are for rates waaaaay lower than 10.75%. The trick here is to be sure you can either pay off the loan in the time frame the low rate applies, or be prepared for rates way HIGHER than Disney's 10.75%
Try your local bank, your local credit union. If you own a house, inquire about a home equity loan. See if your credit card company has a loan offer that you qualify for...
Now, if you finance thru Disney it qualifies as a mortgage, setting up mortgage interest tax deduction possibilities...that won't be available if you don't set the loan up as a mortgage...I've never tried to finance any kind of time share as a mortgage, but am told it's next to impossible...
So...if you determine that for your family the value of "access" to Disney World while your kids are young outweighs the overall cost to your budget, then what you really want to do is find the best possible loan. The credit card offers will generally be short-term, and thus may not be worth exploring...but the personal loans available thru banks & credit unions (these days they're harder to get--but they still exist for people w/great credit) may be an avenue that will work for you.
While you're looking at your "comfort zone" for a monthly payment, don't forget to add in maintenance fees...they run about $5/point (they can be paid monthly thru auto deduct from a checking account, at no fee)...so on 100 points, that would be $500, or about $40/month...you may or may not have factored that in to your $100/month "comfortable payment"...if you did, hurray...if not, you're really looking for a loan that can be repaid at the rate of $60/month...
Good luck!