Why

10–50 inbound web form + email leads/month is low volume, but you have 4–10 people who can each assume "someone else got that one." Inbound SaaS leads decay in hours, not days — and email + web form is the exact combo where a missed assignment looks like silence to the prospect. You're past the spreadsheet threshold purely because of team size, not lead volume.

What you actually need

1. HubSpot Free CRM (free for unlimited users) — connect your team's shared inbox and point your web form's submission to it. Every inquiry becomes a contact with an owner field, automatically round-robined or manually claimed.
2. A single pipeline with four stages — New → Qualified → Demo/Trial → Closed. No custom fields, no lead scoring, no sequences yet. Just owner + next-action date on every deal.
3. A habit — the 10am standup pipeline scan — one person (sales lead) opens the "no activity in 48h" filter daily and reassigns or nudges. Five minutes.

Do this today

Sign up at hubspot.com/products/crm (free tier), then go to Settings → Inbox → Connect a channel and connect your shared sales email. Next, replace your web form's destination: in HubSpot go to Marketing → Forms → Create form, embed the new form on your site (or use a webhook from your existing form). By tomorrow morning every inbound email and form fill lands as an assignable contact with a timestamp.

What to ignore

Skip HubSpot Sales Hub Professional ($100/seat/mo) and Starter ($20/seat/mo) — the free tier covers everything you need at 10–50 leads/month with 4–10 users, and the upsell pressure begins the moment you talk to a rep. Ignore Salesforce entirely at this stage; it's a six-month implementation for a problem you can solve this afternoon. Apollo, Outreach, and Salesloft are outbound tools — you said inbound organic, so they don't apply.

What doing nothing costs you

A conservative 20% slippage on 50 inbound SaaS leads/month (because nobody owns them) = ~10 lost qualified leads. For an organic inbound SaaS lead — already self-selected and warm — that's the most expensive kind of leak you can have.

When to revisit this

When inbound crosses 200/month or you start running outbound campaigns — then the free tier's reporting and automation limits start hurting.