Beach front property all over ambergris is $1,500.-$3,000. USD a linear foot. That would make a lot of min. size (75feet) over 100 thousand USD., so if its considerably cheaper than than that you should look real hard for some problem,like only accessible by helicopter and only at certain times of the year :-)or limited ownership.
Some of the properties for sale at the extreme north end of the island are not practical to build on.IMHO

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