On Jun 30, 8:06*pm, "
wrote:
Is it worth it to save the extra money to use this from Heathrow
Terminals 123 [London Underground] to Upminster saving £1.10?

Alternative oyster single fares:
Route 1: Avoiding Zone 1 via any of Kensington Olympia, Shepherds Bush
or West Brompton
[snip]
Route 2: Avoiding Zone 1 via Gospel Oak
[snip]
Route 3: Avoiding Zone 1 via Stratford (London Overground)
[snip]

No, I don't think so. Unless you really want an excuse to go via a
more labyrinthine route!

(Also, note that not all trains to Tilbury stop at Upminster during
peak periods.)