Write one list of the need you are comparing
Suppose two adults need beans, pasta and exactly one jar of sauce for a specified dinner. Record the packs each shop actually sells and the amounts you would have to take home. Comparable ingredients need not come in identical packages, but an extra package changes the cash needed at checkout.
Compare two complete checkout totals
Shop A has $9 in beans and pasta, a $6 sauce two-pack and $3 delivery: $18. Shop B has $10 in beans and pasta, a $4 single jar and free collection: $14 before the trip. If collection requires a separate $2 bus fare, its immediate cost becomes $16. The spare sauce at A is useful only if someone wants it later.
Check a discount at the point it applies
If the cheaper basket depends on using a voucher, check that it applies to the household’s order before relying on it. If both baskets cost about the same, use the collection time or an inconvenient substitution to decide between them.
If Shop A offers $4 off an order with a $20 merchandise subtotal, the $15 merchandise basket does not qualify. Delivery alone will not meet a merchandise threshold. Read the offer and total the items you would otherwise buy before adding anything solely to unlock it.