multiple table data retrieval with function

I want to retrieve similar data from two tables then add those two results together.

How would I do this:

Table one
Id1, bloggs, tuition fees (40)

Table two
Id1, bloggs, tuition fees (10)
Id2, bloggs, tuition fees (20)
Id2, bloggs, tuition fees (10)

Recordset:
Id1 bloggs tuition fees (40)
Id1, bloggs, tuition fees (10)
Id2, bloggs, tuition fees (20)
Id2, bloggs, tuition fees (10)

total should be tuition fees = 80

Here I want to search on 'bloggs' then add the tuition fees together. How do I not get duplicate data. I have tried different joins and unions but am getting confused by the whole busines.

SELECT dbo.payments.tuition, dbo.paymentAdd.tuition AS tuition2
FROM dbo.payments FULL OUTER JOIN
dbo.paymentAdd ON dbo.payments.student_id = dbo.paymentAdd.student_id

Many thanks for any help.