Fully agree. Sometimes the best equipment is that which is in-hand and thus free.
you can just send vlan tagged traffic across a dumb switch no problem
A small word of caution: some cheap unmanaged switches rigidly enforce 1500 Byte payload sizes, and if the switch has no clue that 802.1q VLAN tags even exist, will consider the extra 4 bytes as part of the payload. So your workable MTU for tagged traffic could now be 1496 Bytes.
Most traffic will likely traverse that switch just fine, but max-sized 1500 Byte payload frames with a VLAN tag may be dropped or cause checksum errors. Large file transfers tend to use the full MTU, so be aware of this if you see strange issues specific to tagged traffic.