What are the reasons your lawyer is recommending the trust? You need to know exactly what this accomplishes, since trusts are crafted for specific issues -- there is no "universal" trust or even Will. I agree that $700 sounds very low.
We considered 3 scenarios for our estate planning: 1 spouse dies, both parents die, entire family dies. We then came up with a disposition for each, & they are very different. For 1 spouse dead, the other inherits the spouse's estate, no guardianship provision needed, but you may want a trust created for the children should the remaining parent remarry. For both parents dead, either together or after the first, the will should specify guardianship for the children & create a trust for them. The person or entity managing the trust does not have to be & likely should not be the guardian, because s/he might not be financially savvy, but the trust should provide compensation to the guardian as well as support the children. For entire family dead, we split the value of the estate in half for each spouse, who then designated percentages to leave to family & charities.
Our son is now an adult, so we've revised our wills to create trusts for deferring estate taxes, but this is usually feasible with estates over $5 million.