You can find everything you need to know about inoculations and immunizations for traveling to Nicaragua on the following U.S. Center for Disease Control website.
Regarding cost, it is difficult to estimate as different insurance companies are willing to pay different amounts. A rule of thumb here is that the local county health departments will probably provide you with the best cost for the inoculations. Assuredly, the county health department may be the only place you can obtain the Typhoid vaccine.
A note on the Typhoid vaccine, there are two types:
The more common is the vaccine administered by injection. The injection is administered in a single office visit, is normally less expensive, but is good for only three years before a booster must be administered. The other option, oral tablets, are a series of tablets that must be refrigerated until taken, and a tablet is taken every other day until all tablets are taken. This is the lesser used option as it requires a greater effort to remember to take all the tablets on schedule over several days, it normally cost a little more but does have the one advantage of not requiring a booster for a period of five years. Unless you plan to travel somewhere requiring a Typhoid vaccine often then the simpler choice is the one time visit for the injection. To be fully effective Typhoid vaccinations must be done at least 30 days prior to departure.
A note concerning both the Hepatitis A, and Hepatitis B vaccinations:
These vaccinations are administered as a series of injections over three office visits. Following the first injection a second injection is required in thirty days and the final injection is six months after the first injection. It would be best to have the series complete before departure but the final injection, administered six months after the first injection, can be done following the trip. For your safety please begin these injections no later than 90 days before departure.
The most used anti-malaria medication is chloroquine tablets. These come in tablet form and a tablet is taken once a week beginning a week or two before departure and continuing for about four weeks after returning. How long a person takes the tablets is recommended by your medical practitioner. Different doctors sometimes recommend different number of pills to be taken. Most people find that they will be taking one tablet each week for a period of five weeks; beginning one week before departure.