Script is outputting the incorrect item, any help?

The reason it is printing nil is because you are searching the table t for "Hot Dog", however, it only has tables inside of itself. Instead, you should search each sub-table:

local t = {
    {"Burger",1000},
    {"Taco",5000},
    {"Hot Dog",150000},
    {"Steak",60},
    {"Grilled Cheese",10}
}
for i, tbl in pairs(t) do
    local number = tbl[2]
    print(number)
    print(table.find(tbl,"Hot Dog"))
end

-- Output:
-- 1000
-- nil 
-- 5000
-- nil
-- 150000
-- 1<-- This is where "Hot Dog" is located.
-- 60
-- nil
-- 10
-- nil

Here is a script I toke from roblox references] https://developer.roblox.com/en-us/api-reference/lua-docs/table

local t = {"a", "b", "c", "d", "e"}

print(table.find(t, "d")) --> 4
print(table.find(t, "z")) --> nil, because z is not in the table
print(table.find(t, "b", 3)) --> nil, because b appears before index 3

Judging from that script maybe try changing yours to

local t = {"Burger",1000, "Taco",5000,"Hot Dog",150000,  "Steak",60, "Grilled Cheese",10}

for i, number in pairs(t) do
    print(number)
    print(table.find(t,"Hot Dog",5))
end