As mentioned above, it's not clear if you're talking about the NRMP match, or ERAS application. Fees are different for both. Assuming NRMP:
Here's the info from the NRMP website:
Registration Fee
Payment of the $50.00 registration fee for U.S. seniors must be made at the time of registration for the Main Residency Match. Applicants who complete their registrations after November 30th must pay an additional $50 late registration fee. All registration fees are non-refundable.
By electing to pay by credit card or electronic banking, the applicant authorizes the NRMP to supply the applicant's bank with information it requires about your NRMP Agreement to resolve any inquiries concerning related charges.
Registration entitles the applicant to the following NRMP services:
Access to the NRMP R3 site;
Processing of up to 20 different program ranks on the primary rank order list at no additional cost (for each additional program over 20, the fee is $30 per program);
Processing of up to 20 different program ranks on supplemental rank order lists at no additional charge, regardless of the number of supplemental rank order lists having combinations of those programs (for each additional program over 20, the fee is $30 per program);
Each partner of a couple may rank up to 30 different programs on the primary rank order list and up to 30 programs on all supplemental lists combined at no additional charge. Each partner of a couple also must pay an additional $15 registration fee.
So, what does this mean for you?
The basic fee will be $50+$15 for each of you (assuming you register before Nov 30, or tack on another $50 late fee). That allows you to rank 30 programs each. You are allowed to rank each program as many times as you want. Thus, if you listed as a couple all possible combinations (including the possibilities that one of you matches and the other doesn't), there would be (31*31)-1=960 ranks on each of your ranklists, and you'd still only owe the basic fee. So far, so good.
Life becomes expensive when you start to rank more than this. It's $30 PER PROGRAM. The NRMP does this because, honestly, there isn't much point to ranking more than 30 programs. If you have that many interviews, you'll likely match somewhere with 30 ranks.
So, to answer your question, you'd be ranking your 100 Program A and 30 Program B on your rank lists. The internships would go on your supplemental, so we'll deal with that later. That's 130 programs. The first 30 are included, so you'd have 100 extras. $30 each, so that's $3000. The internships would go on a supplemental list, the first 30 are included. You'd have 20 extra of those, also $30 each, so that's another $600.
You'd also have to decide whether you wanted to list the interships on your primary list. You'd do this in case you didn't match in either specialty A or B, to get just an internship. If you did that, you'd likely get charged another $30 x 50 = $1500.
Anyway, all of this is kinda pointless. You may APPLY to 100 programs, but you're unlikely to RANK 100 programs. You'd never be able to go on 100 interviews!
The key is this: in the NRMP couples match, you only pay for UNIQUE program ranks. The couple's list becomes really long quickly, but you get 30 unique programs to rank for your initial fee, and you can include each program as many times as you want on your list (each one paired with a different program on your partner's list) for no cost.
Now, if you were wondering how much this would cost to APPLY in ERAS, that's easy. Here's a calculator:
https://www.residencyplace.com/ErasCalcPage.aspx
